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        <link:definition>9955524 - Disclosure - INCOME TAXES (Tables)</link:definition>
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        <link:definition>9955526 - Disclosure - SEGMENT INFORMATION (Tables)</link:definition>
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        <link:definition>9955527 - Disclosure - DESCRIPTION OF BUSINESS (Details)</link:definition>
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        <link:definition>9955528 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)</link:definition>
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        <link:definition>9955529 - Disclosure - GQ BIO THERAPEUTICS ACQUISITION - Narrative (Details)</link:definition>
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        <link:definition>9955530 - Disclosure - GQ BIO THERAPEUTICS ACQUISITION - Schedule of Reconciliation of Purchase Price to Total Consideration Transferred (Details)</link:definition>
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        <link:definition>9955531 - Disclosure - GQ BIO THERAPEUTICS ACQUISITION - Schedule of Indicates the Consideration Transferred to Effect the Acquisition of GQ Bio (Details)</link:definition>
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  <xs:element id="pcrx_SellingAndMarketingAdjusted" abstract="false" name="SellingAndMarketingAdjusted" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_SellingGeneralAndAdministrativeAdjusted" abstract="false" name="SellingGeneralAndAdministrativeAdjusted" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_OtherIncomeExpenseAdjusted" abstract="false" name="OtherIncomeExpenseAdjusted" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_AmacaTheraIncMember" abstract="true" name="AmacaTheraIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_AdvanceMilestonePayments" abstract="false" name="AdvanceMilestonePayments" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="pcrx_JonathanSloninMember" abstract="true" name="JonathanSloninMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_KristenWilliamsMember" abstract="true" name="KristenWilliamsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
