<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2022 Workiva-->
<!--r:1acf2e72-2487-45a7-a11c-6bf309df42b1,g:86a623c9-da96-4e80-aae2-29b4daaaad57-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:pcrx="http://www.pacira.com/20220630" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2020-01-21" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.pacira.com/20220630">
  <xs:import namespace="http://fasb.org/srt/2022" schemaLocation="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2022" schemaLocation="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd"/>
  <xs:import namespace="http://www.w3.org/1999/xlink" schemaLocation="http://www.xbrl.org/2003/xlink-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2020-01-21" schemaLocation="https://www.xbrl.org/dtr/type/2020-01-21/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2022" schemaLocation="https://xbrl.sec.gov/dei/2022/dei-2022.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="pcrx-20220630_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="pcrx-20220630_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="pcrx-20220630_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="pcrx-20220630_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="CoverPage" roleURI="http://www.pacira.com/role/CoverPage">
        <link:definition>0001001 - Document - Cover Page</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDBALANCESHEETS" roleURI="http://www.pacira.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETS">
        <link:definition>1001002 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical" roleURI="http://www.pacira.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSParenthetical">
        <link:definition>1002003 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS" roleURI="http://www.pacira.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONS">
        <link:definition>1003004 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME" roleURI="http://www.pacira.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOME">
        <link:definition>1004005 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" roleURI="http://www.pacira.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY">
        <link:definition>1005006 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS" roleURI="http://www.pacira.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWS">
        <link:definition>1006007 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DESCRIPTIONOFBUSINESS" roleURI="http://www.pacira.com/role/DESCRIPTIONOFBUSINESS">
        <link:definition>2101101 - Disclosure - DESCRIPTION OF BUSINESS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DESCRIPTIONOFBUSINESSDetails" roleURI="http://www.pacira.com/role/DESCRIPTIONOFBUSINESSDetails">
        <link:definition>2402401 - Disclosure - DESCRIPTION OF BUSINESS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES" roleURI="http://www.pacira.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES">
        <link:definition>2103102 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies" roleURI="http://www.pacira.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies">
        <link:definition>2204201 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESTables" roleURI="http://www.pacira.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESTables">
        <link:definition>2305301 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESScheduleofConcentrationRiskofMajorCustomersDetails" roleURI="http://www.pacira.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESScheduleofConcentrationRiskofMajorCustomersDetails">
        <link:definition>2406402 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Concentration Risk of Major Customers (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNewAccountingPronouncementsDetails" roleURI="http://www.pacira.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESNewAccountingPronouncementsDetails">
        <link:definition>2407403 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - New Accounting Pronouncements (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="REVENUE" roleURI="http://www.pacira.com/role/REVENUE">
        <link:definition>2108103 - Disclosure - REVENUE</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="REVENUETables" roleURI="http://www.pacira.com/role/REVENUETables">
        <link:definition>2309302 - Disclosure - REVENUE (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="REVENUENarrativeDetails" roleURI="http://www.pacira.com/role/REVENUENarrativeDetails">
        <link:definition>2410404 - Disclosure - REVENUE - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="REVENUEScheduleofDisaggregatedRevenueDetails" roleURI="http://www.pacira.com/role/REVENUEScheduleofDisaggregatedRevenueDetails">
        <link:definition>2411405 - Disclosure - REVENUE - Schedule of Disaggregated Revenue (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FLEXIONACQUISITION" roleURI="http://www.pacira.com/role/FLEXIONACQUISITION">
        <link:definition>2112104 - Disclosure - FLEXION ACQUISITION</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FLEXIONACQUISITIONTables" roleURI="http://www.pacira.com/role/FLEXIONACQUISITIONTables">
        <link:definition>2313303 - Disclosure - FLEXION ACQUISITION (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FLEXIONACQUISITIONNarrativeDetails" roleURI="http://www.pacira.com/role/FLEXIONACQUISITIONNarrativeDetails">
        <link:definition>2414406 - Disclosure - FLEXION ACQUISITION - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FLEXIONACQUISITIONScheduleofAssetsandLiabilitiesDetails" roleURI="http://www.pacira.com/role/FLEXIONACQUISITIONScheduleofAssetsandLiabilitiesDetails">
        <link:definition>2415407 - Disclosure - FLEXION ACQUISITION - Schedule of Assets and Liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FLEXIONACQUISITIONScheduleofProFormaInformationDetails" roleURI="http://www.pacira.com/role/FLEXIONACQUISITIONScheduleofProFormaInformationDetails">
        <link:definition>2416408 - Disclosure - FLEXION ACQUISITION - Schedule of Pro Forma Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIES" roleURI="http://www.pacira.com/role/INVENTORIES">
        <link:definition>2117105 - Disclosure - INVENTORIES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIESTables" roleURI="http://www.pacira.com/role/INVENTORIESTables">
        <link:definition>2318304 - Disclosure - INVENTORIES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INVENTORIESDetails" roleURI="http://www.pacira.com/role/INVENTORIESDetails">
        <link:definition>2419409 - Disclosure - INVENTORIES (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FIXEDASSETS" roleURI="http://www.pacira.com/role/FIXEDASSETS">
        <link:definition>2120106 - Disclosure - FIXED ASSETS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FIXEDASSETSTables" roleURI="http://www.pacira.com/role/FIXEDASSETSTables">
        <link:definition>2321305 - Disclosure - FIXED ASSETS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FIXEDASSETSSummaryofMajorCategoriesDetails" roleURI="http://www.pacira.com/role/FIXEDASSETSSummaryofMajorCategoriesDetails">
        <link:definition>2422410 - Disclosure - FIXED ASSETS - Summary of Major Categories (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FIXEDASSETSNarrativeDetails" roleURI="http://www.pacira.com/role/FIXEDASSETSNarrativeDetails">
        <link:definition>2423411 - Disclosure - FIXED ASSETS - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LEASES" roleURI="http://www.pacira.com/role/LEASES">
        <link:definition>2124107 - Disclosure - LEASES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LEASESTables" roleURI="http://www.pacira.com/role/LEASESTables">
        <link:definition>2325306 - Disclosure - LEASES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LEASESNarrativeDetails" roleURI="http://www.pacira.com/role/LEASESNarrativeDetails">
        <link:definition>2426412 - Disclosure - LEASES - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LEASESSummaryofoperatingleasecostandotheroperatingleaseinformationDetails" roleURI="http://www.pacira.com/role/LEASESSummaryofoperatingleasecostandotheroperatingleaseinformationDetails">
        <link:definition>2427413 - Disclosure - LEASES - Summary of operating lease cost and other operating lease information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LEASESScheduleofmaturitiesofoperatingleaseliabilitiesDetails" roleURI="http://www.pacira.com/role/LEASESScheduleofmaturitiesofoperatingleaseliabilitiesDetails">
        <link:definition>2428414 - Disclosure - LEASES - Schedule of maturities of operating lease liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LEASESScheduleofmaturitiesofoperatingleaseliabilitiesDetails_1" roleURI="http://www.pacira.com/role/LEASESScheduleofmaturitiesofoperatingleaseliabilitiesDetails_1">
        <link:definition>2428414 - Disclosure - LEASES - Schedule of maturities of operating lease liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LEASESScheduleofmaturitiesofoperatingleaseliabilitiesleasenotyetcommencedDetails" roleURI="http://www.pacira.com/role/LEASESScheduleofmaturitiesofoperatingleaseliabilitiesleasenotyetcommencedDetails">
        <link:definition>2429415 - Disclosure - LEASES -Schedule of maturities of operating lease liabilities (lease not yet commenced) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETS" roleURI="http://www.pacira.com/role/GOODWILLANDINTANGIBLEASSETS">
        <link:definition>2130108 - Disclosure - GOODWILL AND INTANGIBLE ASSETS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSTables" roleURI="http://www.pacira.com/role/GOODWILLANDINTANGIBLEASSETSTables">
        <link:definition>2331307 - Disclosure - GOODWILL AND INTANGIBLE ASSETS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSNarrativeDetails" roleURI="http://www.pacira.com/role/GOODWILLANDINTANGIBLEASSETSNarrativeDetails">
        <link:definition>2432416 - Disclosure - GOODWILL AND INTANGIBLE ASSETS - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GOODWILLANDINTANGIBLEASSETSIntangibleAssetsDetails" roleURI="http://www.pacira.com/role/GOODWILLANDINTANGIBLEASSETSIntangibleAssetsDetails">
        <link:definition>2433417 - Disclosure - GOODWILL AND INTANGIBLE ASSETS - Intangible Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBT" roleURI="http://www.pacira.com/role/DEBT">
        <link:definition>2134109 - Disclosure - DEBT</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTTables" roleURI="http://www.pacira.com/role/DEBTTables">
        <link:definition>2335308 - Disclosure - DEBT (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTCarryingValueofDebtDetails" roleURI="http://www.pacira.com/role/DEBTCarryingValueofDebtDetails">
        <link:definition>2436418 - Disclosure - DEBT - Carrying Value of Debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTNarrativeDetails" roleURI="http://www.pacira.com/role/DEBTNarrativeDetails">
        <link:definition>2437419 - Disclosure - DEBT - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTScheduleofDebtDetails" roleURI="http://www.pacira.com/role/DEBTScheduleofDebtDetails">
        <link:definition>2438420 - Disclosure - DEBT - Schedule of Debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DEBTScheduleofInterestExpenseDetails" roleURI="http://www.pacira.com/role/DEBTScheduleofInterestExpenseDetails">
        <link:definition>2439421 - Disclosure - DEBT - Schedule of Interest Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FINANCIALINSTRUMENTS" roleURI="http://www.pacira.com/role/FINANCIALINSTRUMENTS">
        <link:definition>2140110 - Disclosure - FINANCIAL INSTRUMENTS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FINANCIALINSTRUMENTSTables" roleURI="http://www.pacira.com/role/FINANCIALINSTRUMENTSTables">
        <link:definition>2341309 - Disclosure - FINANCIAL INSTRUMENTS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FINANCIALINSTRUMENTSFairValueofLiabilitiesMeasuredonaRecurringBasisDetails" roleURI="http://www.pacira.com/role/FINANCIALINSTRUMENTSFairValueofLiabilitiesMeasuredonaRecurringBasisDetails">
        <link:definition>2442422 - Disclosure - FINANCIAL INSTRUMENTS - Fair Value of Liabilities Measured on a Recurring Basis (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FINANCIALINSTRUMENTSScheduleofInvestmentsWithoutReadilyDeterminableFairValueDetails" roleURI="http://www.pacira.com/role/FINANCIALINSTRUMENTSScheduleofInvestmentsWithoutReadilyDeterminableFairValueDetails">
        <link:definition>2443423 - Disclosure - FINANCIAL INSTRUMENTS - Schedule of Investments Without Readily Determinable Fair Value (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FINANCIALINSTRUMENTSNarrativeDetails" roleURI="http://www.pacira.com/role/FINANCIALINSTRUMENTSNarrativeDetails">
        <link:definition>2444424 - Disclosure - FINANCIAL INSTRUMENTS - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FINANCIALINSTRUMENTSFairValueMeasurementInputsandValuationDetails" roleURI="http://www.pacira.com/role/FINANCIALINSTRUMENTSFairValueMeasurementInputsandValuationDetails">
        <link:definition>2445425 - Disclosure - FINANCIAL INSTRUMENTS - Fair Value Measurement Inputs and Valuation (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FINANCIALINSTRUMENTSFairValueofContingentConsiderationRollforwardDetails" roleURI="http://www.pacira.com/role/FINANCIALINSTRUMENTSFairValueofContingentConsiderationRollforwardDetails">
        <link:definition>2446426 - Disclosure - FINANCIAL INSTRUMENTS - Fair Value of Contingent Consideration Rollforward (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FINANCIALINSTRUMENTSScheduleofAvailableForSaleSecuritiesDetails" roleURI="http://www.pacira.com/role/FINANCIALINSTRUMENTSScheduleofAvailableForSaleSecuritiesDetails">
        <link:definition>2447427 - Disclosure - FINANCIAL INSTRUMENTS - Schedule of Available-For-Sale Securities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKHOLDERSEQUITY" roleURI="http://www.pacira.com/role/STOCKHOLDERSEQUITY">
        <link:definition>2148111 - Disclosure - STOCKHOLDERS' EQUITY</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKHOLDERSEQUITYTables" roleURI="http://www.pacira.com/role/STOCKHOLDERSEQUITYTables">
        <link:definition>2349310 - Disclosure - STOCKHOLDERS' EQUITY (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKHOLDERSEQUITYDetails" roleURI="http://www.pacira.com/role/STOCKHOLDERSEQUITYDetails">
        <link:definition>2450428 - Disclosure - STOCKHOLDERS' EQUITY (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKPLANS" roleURI="http://www.pacira.com/role/STOCKPLANS">
        <link:definition>2151112 - Disclosure - STOCK PLANS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKPLANSTables" roleURI="http://www.pacira.com/role/STOCKPLANSTables">
        <link:definition>2352311 - Disclosure - STOCK PLANS (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKPLANSScheduleofStockBasedCompensationExpensesDetails" roleURI="http://www.pacira.com/role/STOCKPLANSScheduleofStockBasedCompensationExpensesDetails">
        <link:definition>2453429 - Disclosure - STOCK PLANS - Schedule of Stock Based Compensation Expenses (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKPLANSScheduleofStockBasedCompensationActivityDetails" roleURI="http://www.pacira.com/role/STOCKPLANSScheduleofStockBasedCompensationActivityDetails">
        <link:definition>2454430 - Disclosure - STOCK PLANS - Schedule of Stock Based Compensation Activity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKPLANSNarrativeDetails" roleURI="http://www.pacira.com/role/STOCKPLANSNarrativeDetails">
        <link:definition>2455431 - Disclosure - STOCK PLANS - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="STOCKPLANSScheduleofValuationAssumptionsDetails" roleURI="http://www.pacira.com/role/STOCKPLANSScheduleofValuationAssumptionsDetails">
        <link:definition>2456432 - Disclosure - STOCK PLANS - Schedule of Valuation Assumptions (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NETINCOMELOSSPERSHARE" roleURI="http://www.pacira.com/role/NETINCOMELOSSPERSHARE">
        <link:definition>2157113 - Disclosure - NET INCOME (LOSS) PER SHARE</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NETINCOMELOSSPERSHARETables" roleURI="http://www.pacira.com/role/NETINCOMELOSSPERSHARETables">
        <link:definition>2358312 - Disclosure - NET INCOME (LOSS) PER SHARE (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NETINCOMELOSSPERSHAREScheduleofComputationofEPSDetails" roleURI="http://www.pacira.com/role/NETINCOMELOSSPERSHAREScheduleofComputationofEPSDetails">
        <link:definition>2459433 - Disclosure - NET INCOME (LOSS) PER SHARE - Schedule of Computation of EPS (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NETINCOMELOSSPERSHAREScheduleofAntidilutiveSecuritiesDetails" roleURI="http://www.pacira.com/role/NETINCOMELOSSPERSHAREScheduleofAntidilutiveSecuritiesDetails">
        <link:definition>2460434 - Disclosure - NET INCOME (LOSS) PER SHARE - Schedule of Antidilutive Securities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INCOMETAXES" roleURI="http://www.pacira.com/role/INCOMETAXES">
        <link:definition>2161114 - Disclosure - INCOME TAXES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INCOMETAXESTables" roleURI="http://www.pacira.com/role/INCOMETAXESTables">
        <link:definition>2362313 - Disclosure - INCOME TAXES (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="INCOMETAXESScheduleofFederalStateandLocalandForeignIncomeTaxesDetails" roleURI="http://www.pacira.com/role/INCOMETAXESScheduleofFederalStateandLocalandForeignIncomeTaxesDetails">
        <link:definition>2463435 - Disclosure - INCOME TAXES - Schedule of Federal, State and Local, and Foreign Income Taxes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACQUISITIONRELATEDGAINSCHARGESPRODUCTDISCONTINUATIONANDOTHER" roleURI="http://www.pacira.com/role/ACQUISITIONRELATEDGAINSCHARGESPRODUCTDISCONTINUATIONANDOTHER">
        <link:definition>2164115 - Disclosure - ACQUISITION&#8211;RELATED (GAINS) CHARGES, PRODUCT DISCONTINUATION AND OTHER</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACQUISITIONRELATEDGAINSCHARGESPRODUCTDISCONTINUATIONANDOTHERTables" roleURI="http://www.pacira.com/role/ACQUISITIONRELATEDGAINSCHARGESPRODUCTDISCONTINUATIONANDOTHERTables">
        <link:definition>2365314 - Disclosure - ACQUISITION&#8211;RELATED (GAINS) CHARGES, PRODUCT DISCONTINUATION AND OTHER (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACQUISITIONRELATEDGAINSCHARGESPRODUCTDISCONTINUATIONANDOTHERProductDiscontinuanceDetails" roleURI="http://www.pacira.com/role/ACQUISITIONRELATEDGAINSCHARGESPRODUCTDISCONTINUATIONANDOTHERProductDiscontinuanceDetails">
        <link:definition>2466436 - Disclosure - ACQUISITION&#8211;RELATED (GAINS) CHARGES, PRODUCT DISCONTINUATION AND OTHER - Product Discontinuance (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ACQUISITIONRELATEDGAINSCHARGESPRODUCTDISCONTINUATIONANDOTHERNarrativeDetails" roleURI="http://www.pacira.com/role/ACQUISITIONRELATEDGAINSCHARGESPRODUCTDISCONTINUATIONANDOTHERNarrativeDetails">
        <link:definition>2467437 - Disclosure - ACQUISITION&#8211;RELATED (GAINS) CHARGES, PRODUCT DISCONTINUATION AND OTHER - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="COMMITMENTSANDCONTINGENCIES" roleURI="http://www.pacira.com/role/COMMITMENTSANDCONTINGENCIES">
        <link:definition>2168116 - Disclosure - COMMITMENTS AND CONTINGENCIES</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="COMMITMENTSANDCONTINGENCIESDetails" roleURI="http://www.pacira.com/role/COMMITMENTSANDCONTINGENCIESDetails">
        <link:definition>2469438 - Disclosure - COMMITMENTS AND CONTINGENCIES (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="pcrx_DebtInstrumentPercentageOfPrincipalAmountForComputationOfRedemptionPrice" abstract="false" name="DebtInstrumentPercentageOfPrincipalAmountForComputationOfRedemptionPrice" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="pcrx_LesseeOperatingLeaseLeaseNotYetCommencedLiability" abstract="false" name="LesseeOperatingLeaseLeaseNotYetCommencedLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_UponAnnualNetSalesReachingDollar500.0MillionThresholdMember" abstract="true" name="UponAnnualNetSalesReachingDollar500.0MillionThresholdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_DebtInstrumentConvertibleConversionPremiumShares" abstract="false" name="DebtInstrumentConvertibleConversionPremiumShares" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="pcrx_ProceedsFromSharesIssuedUnderEmployeeStockPurchasePlans" abstract="false" name="ProceedsFromSharesIssuedUnderEmployeeStockPurchasePlans" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedExpenses" abstract="false" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedExpenses" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_DebtInstrumentCovenantLeverageRatioMaximum" abstract="false" name="DebtInstrumentCovenantLeverageRatioMaximum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="pcrx_NuanceBiotechCo.Ltd.Member" abstract="true" name="NuanceBiotechCo.Ltd.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_BusinessCombinationConsiderationTransferredLiabilitiesIncurredDebt" abstract="false" name="BusinessCombinationConsiderationTransferredLiabilitiesIncurredDebt" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPurchasePeriods" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPurchasePeriods" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="pcrx_FlexionAcquisitionMember" abstract="true" name="FlexionAcquisitionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_AmortizationOfOtherAssetsAndUnfavorableLeaseObligation" abstract="false" name="AmortizationOfOtherAssetsAndUnfavorableLeaseObligation" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_EarningsPerShareBasicAndDilutedEPSAbstract" abstract="true" name="EarningsPerShareBasicAndDilutedEPSAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="pcrx_ComputerEquipmentAndSoftwareMember" abstract="true" name="ComputerEquipmentAndSoftwareMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_NumberOfLeases" abstract="false" name="NumberOfLeases" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="pcrx_LesseeOperatingLeaseLeaseNotYetCommencedNumberOfContracts" abstract="false" name="LesseeOperatingLeaseLeaseNotYetCommencedNumberOfContracts" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="pcrx_LargestCustomerMember" abstract="true" name="LargestCustomerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_IoveraMember" abstract="true" name="IoveraMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_MajorCustomerTwoMember" abstract="true" name="MajorCustomerTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_ContingentConsiderationMember" abstract="true" name="ContingentConsiderationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_EmployeeStockPurchasePlansSharesAmountAuthorizedToBeSoldDuringPeriodIncrease" abstract="false" name="EmployeeStockPurchasePlansSharesAmountAuthorizedToBeSoldDuringPeriodIncrease" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="pcrx_AcquisitionRelatedGainLossProductDiscontinuationCostsAndOtherNet" abstract="false" name="AcquisitionRelatedGainLossProductDiscontinuationCostsAndOtherNet" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_DebtInstrumentBasisSpreadTwoOnVariableRate" abstract="false" name="DebtInstrumentBasisSpreadTwoOnVariableRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="pcrx_SkyePharmaHoldingIncMember" abstract="true" name="SkyePharmaHoldingIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_LesseeOperatingLeaseLeaseNotYetCommencedLiabilityDueYearThree" abstract="false" name="LesseeOperatingLeaseLeaseNotYetCommencedLiabilityDueYearThree" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ThreeLargestCustomersMember" abstract="true" name="ThreeLargestCustomersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_ConvertibleNotesReceivableMember" abstract="true" name="ConvertibleNotesReceivableMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_AccountsReceivablePaymentTerms" abstract="false" name="AccountsReceivablePaymentTerms" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="pcrx_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" abstract="false" name="LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_COMMERCIALPARTNERSANDOTHERAGREEMENTSTableTextBlock" abstract="false" name="COMMERCIALPARTNERSANDOTHERAGREEMENTSTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="pcrx_LesseeOperatingLeaseLeaseNotYetCommencedLiabilityDueAfterYearFour" abstract="false" name="LesseeOperatingLeaseLeaseNotYetCommencedLiabilityDueAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_MyoscienceAcquisitionMember" abstract="true" name="MyoscienceAcquisitionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_MeasurementInputExpectedMilestonePaymentMember" abstract="true" name="MeasurementInputExpectedMilestonePaymentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetForeignCurrencyGainLoss" abstract="false" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetForeignCurrencyGainLoss" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_DebtInstrumentPrepaymentPenaltyPercentYear1" abstract="false" name="DebtInstrumentPrepaymentPenaltyPercentYear1" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="pcrx_ConcentrationRiskNumberOfCustomers" abstract="false" name="ConcentrationRiskNumberOfCustomers" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="pcrx_ConvertibleSeniorNotesDueMay2024Member" abstract="true" name="ConvertibleSeniorNotesDueMay2024Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_DebtConversionConvertedInstrumentWarrantsOrRightsIssuedPerPrincipalAmount" abstract="false" name="DebtConversionConvertedInstrumentWarrantsOrRightsIssuedPerPrincipalAmount" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="pcrx_DebtInstrumentMarketPrice" abstract="false" name="DebtInstrumentMarketPrice" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="pcrx_DebtRedemptionTermsOnOrAfterAugust12023Member" abstract="true" name="DebtRedemptionTermsOnOrAfterAugust12023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_ConvertibleSeniorNotesDue2022Member" abstract="true" name="ConvertibleSeniorNotesDue2022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_SecondLargestCustomerMember" abstract="true" name="SecondLargestCustomerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_Compensationexpensefromstockoptionsemployees" abstract="false" name="Compensationexpensefromstockoptionsemployees" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_CompensationExpenseFromEmployeeStockPurchasePlan" abstract="false" name="CompensationExpenseFromEmployeeStockPurchasePlan" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_EXPARELbupivacaineliposomeinjectablesuspensionMember" abstract="true" name="EXPARELbupivacaineliposomeinjectablesuspensionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_DebtConversionAndRedemptionTermsDomain" abstract="true" name="DebtConversionAndRedemptionTermsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_PaymentOfContingentConsideration" abstract="false" name="PaymentOfContingentConsideration" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_FlexionTherapeuticsIncMember" abstract="true" name="FlexionTherapeuticsIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_AcquisitionRelatedFeesMember" abstract="true" name="AcquisitionRelatedFeesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_FederalReserveBankOfNYRateMember" abstract="true" name="FederalReserveBankOfNYRateMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_LegalFeesMember" abstract="true" name="LegalFeesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_MajorCustomerOneMember" abstract="true" name="MajorCustomerOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_MajorCustomerThreeMember" abstract="true" name="MajorCustomerThreeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_DebtInstrumentVariableRate" abstract="false" name="DebtInstrumentVariableRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="pcrx_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentLiabilities" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_DebtRedemptionTermsPriorToFebruary32023Member" abstract="true" name="DebtRedemptionTermsPriorToFebruary32023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_LesseeOperatingLeaseLeaseNotYetCommencedLiabilityDueYearTwo" abstract="false" name="LesseeOperatingLeaseLeaseNotYetCommencedLiabilityDueYearTwo" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ConvertibleSeniorNotesDue2025Member" abstract="true" name="ConvertibleSeniorNotesDue2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAssets" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentNetAssets" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentNetAssets" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ConcentrationRiskNumberOfProducts" abstract="false" name="ConcentrationRiskNumberOfProducts" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="pcrx_HongKongPharmaTainuoLtdMember" abstract="true" name="HongKongPharmaTainuoLtdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_LesseeOperatingLeaseLeaseNotYetCommencedLiabilityDueYearFour" abstract="false" name="LesseeOperatingLeaseLeaseNotYetCommencedLiabilityDueYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_StageAtWhichMilestonePaymentsForProductArePayableInConnectionWithAcquisitionDomain" abstract="true" name="StageAtWhichMilestonePaymentsForProductArePayableInConnectionWithAcquisitionDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_BusinessCombinationConsiderationTransferredLiabilitiesIncurredContingentConsideration" abstract="false" name="BusinessCombinationConsiderationTransferredLiabilitiesIncurredContingentConsideration" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ContingentConsiderationPaymentTerm" abstract="false" name="ContingentConsiderationPaymentTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="pcrx_ZILRETTAMember" abstract="true" name="ZILRETTAMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_LesseeOperatingLeaseLeaseNotYetCommencedLiabilityRemainderOfFiscalYear" abstract="false" name="LesseeOperatingLeaseLeaseNotYetCommencedLiabilityRemainderOfFiscalYear" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_AnnualNetSalesThresholdForDeterminingMilestonePaymentsForProductInConnectionWithAcquisition" abstract="false" name="AnnualNetSalesThresholdForDeterminingMilestonePaymentsForProductInConnectionWithAcquisition" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_AcquisitionRelatedChargesProductDiscontinuationAndOther" abstract="false" name="AcquisitionRelatedChargesProductDiscontinuationAndOther" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_DebtInstrumentDiscountRate" abstract="false" name="DebtInstrumentDiscountRate" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="pcrx_MeasurementInputProbabilityOfSuccessOfRegulatoryMilestonesMember" abstract="true" name="MeasurementInputProbabilityOfSuccessOfRegulatoryMilestonesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_ThirdLargestCustomerMember" abstract="true" name="ThirdLargestCustomerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_SettlementPeriodConvertibleDebtConversionRequest" abstract="false" name="SettlementPeriodConvertibleDebtConversionRequest" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="pcrx_TermLoanBFacilityDue2026Member" abstract="true" name="TermLoanBFacilityDue2026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccruedExpenses" abstract="false" name="BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAccruedExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_FortisMember" abstract="true" name="FortisMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_NumberOfMajorCustomers" abstract="false" name="NumberOfMajorCustomers" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="pcrx_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRightOfUseAssets" abstract="false" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRightOfUseAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_DebtInstrumentPrepaymentPenaltyPercentYear3AndThereafter" abstract="false" name="DebtInstrumentPrepaymentPenaltyPercentYear3AndThereafter" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="pcrx_AgreedMilestonePaymentsForSaleOfProductInConnectionWithAcquisition" abstract="false" name="AgreedMilestonePaymentsForSaleOfProductInConnectionWithAcquisition" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_BupivacaineLiposomeInjectableSuspensionMember" abstract="true" name="BupivacaineLiposomeInjectableSuspensionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_DebtInstrumentBasisSpreadOneOnVariableRate" abstract="false" name="DebtInstrumentBasisSpreadOneOnVariableRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="pcrx_LesseeOperatingLeaseLeaseNotYetCommencedLiabilityDueYearOne" abstract="false" name="LesseeOperatingLeaseLeaseNotYetCommencedLiabilityDueYearOne" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_MajorCustomerFourMember" abstract="true" name="MajorCustomerFourMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_RestrictedStockUnitsMoneyStockOptionsAndCommonStockMember" abstract="true" name="RestrictedStockUnitsMoneyStockOptionsAndCommonStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_MilestonePaymentsForProductInConnectionWithAcquisitionByStageAtWhichTheyArePayableAxis" abstract="true" name="MilestonePaymentsForProductInConnectionWithAcquisitionByStageAtWhichTheyArePayableAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="pcrx_FiniteLivedIntangibleAssetsAmortizationExpenseAnnualAmountPeriod2" abstract="false" name="FiniteLivedIntangibleAssetsAmortizationExpenseAnnualAmountPeriod2" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ProceedsFromDevelopmentAndCommercializationOfZILRETTA" abstract="false" name="ProceedsFromDevelopmentAndCommercializationOfZILRETTA" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_BasisOfPresentationAndPrinciplesOfConsolidationPolicyTextBlock" abstract="false" name="BasisOfPresentationAndPrinciplesOfConsolidationPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="pcrx_CollaborativeArrangementMilestonePaymentsToBeReceivedMaximum" abstract="false" name="CollaborativeArrangementMilestonePaymentsToBeReceivedMaximum" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="pcrx_DebtConversionAndRedemptionTermsAxis" abstract="true" name="DebtConversionAndRedemptionTermsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="pcrx_FlexionAndMyoScienceAcquisitionMember" abstract="true" name="FlexionAndMyoScienceAcquisitionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_FiniteLivedIntangibleAssetsAmortizationExpenseAnnualAmountPeriod1" abstract="false" name="FiniteLivedIntangibleAssetsAmortizationExpenseAnnualAmountPeriod1" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ScheduleOfInterestExpenseTableTextBlock" abstract="false" name="ScheduleOfInterestExpenseTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="pcrx_ConvertibleSeniorNotesDue2024Member" abstract="true" name="ConvertibleSeniorNotesDue2024Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_BusinessCombinationAcquisitionAndIntegrationRelatedCosts" abstract="false" name="BusinessCombinationAcquisitionAndIntegrationRelatedCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_FiniteLivedIntangibleAssetsAmortizationExpenseAnnualAmountPeriod3" abstract="false" name="FiniteLivedIntangibleAssetsAmortizationExpenseAnnualAmountPeriod3" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_CollaborativeLicensingAndMilestoneRevenueMember" abstract="true" name="CollaborativeLicensingAndMilestoneRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_FiniteLivedIntangibleAssetsAmortizationExpenseAnnualAmountPeriod4" abstract="false" name="FiniteLivedIntangibleAssetsAmortizationExpenseAnnualAmountPeriod4" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_DebtInstrumentPeriodicPaymentPrincipalNumberOfPaymentsInNextFiscalYear" abstract="false" name="DebtInstrumentPeriodicPaymentPrincipalNumberOfPaymentsInNextFiscalYear" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="pcrx_DebtInstrumentPrepaymentPenaltyPercentYear2" abstract="false" name="DebtInstrumentPrepaymentPenaltyPercentYear2" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="pcrx_ContingentConsiderationNoncurrent" abstract="false" name="ContingentConsiderationNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ContingentConsiderationCurrent" abstract="false" name="ContingentConsiderationCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ScheduleOfOperatingLeaseNotYetCommencedPaymentsDueTableTextBlock" abstract="false" name="ScheduleOfOperatingLeaseNotYetCommencedPaymentsDueTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="pcrx_EquityMethodInvestmentsAndOtherAssets" abstract="false" name="EquityMethodInvestmentsAndOtherAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_ContingentConsideration" abstract="false" name="ContingentConsideration" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_DebtInstrumentCovenantLeverageRatioMaximumValue" abstract="false" name="DebtInstrumentCovenantLeverageRatioMaximumValue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_DebtInstrumentConversionObligationPremiumOnCommonStock" abstract="false" name="DebtInstrumentConversionObligationPremiumOnCommonStock" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
</xs:schema>
