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  <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_MajorCustomerTwoMember" abstract="true" name="MajorCustomerTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_TermLoanBFacilityDue2026Member" abstract="true" name="TermLoanBFacilityDue2026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_ComputerEquipmentAndSoftwareMember" abstract="true" name="ComputerEquipmentAndSoftwareMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_DebtRedemptionTermsOnOrAfterAugust12023Member" abstract="true" name="DebtRedemptionTermsOnOrAfterAugust12023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <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_SecuredOvernightFinancingRateSOFRMember" abstract="true" name="SecuredOvernightFinancingRateSOFRMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_DebtInstrumentCovenantLeverageRatioMaximum" abstract="false" name="DebtInstrumentCovenantLeverageRatioMaximum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="pcrx_AcquisitionRelatedChargesGainsRestructuringChargesAndOther" abstract="false" name="AcquisitionRelatedChargesGainsRestructuringChargesAndOther" nillable="true" xbrli:periodType="duration" 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-types1:domainItemType"/>
  <xs:element id="pcrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPurchasePeriods" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfPurchasePeriods" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="pcrx_DebtInstrumentMarketPrice" abstract="false" name="DebtInstrumentMarketPrice" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="pcrx_GaryPaceMember" abstract="true" name="GaryPaceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_DebtRedemptionTermsPriorToFebruary32023Member" abstract="true" name="DebtRedemptionTermsPriorToFebruary32023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_IoveraMember" abstract="true" name="IoveraMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_EXPARELbupivacaineliposomeinjectablesuspensionMember" abstract="true" name="EXPARELbupivacaineliposomeinjectablesuspensionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_DebtInstrumentDiscountRate" abstract="false" name="DebtInstrumentDiscountRate" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="pcrx_FlexionAndMyoScienceAcquisitionMember" abstract="true" name="FlexionAndMyoScienceAcquisitionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <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_DirectorsAndExecutiveOfficersTradingArrangementMember" abstract="true" name="DirectorsAndExecutiveOfficersTradingArrangementMember" 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-types1:domainItemType"/>
  <xs:element id="pcrx_SkyePharmaHoldingIncMember" abstract="true" name="SkyePharmaHoldingIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_GaryPacePlanTerminationMember" abstract="true" name="GaryPacePlanTerminationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_TermLoanAFacilityMember" abstract="true" name="TermLoanAFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_EarningsPerShareBasicAndDilutedEPSAbstract" abstract="true" name="EarningsPerShareBasicAndDilutedEPSAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="pcrx_ConcentrationRiskNumberOfProducts" abstract="false" name="ConcentrationRiskNumberOfProducts" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <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_AccountsReceivablePaymentTerms" abstract="false" name="AccountsReceivablePaymentTerms" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="pcrx_LargestCustomerMember" abstract="true" name="LargestCustomerMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_ContingentConsiderationMember" abstract="true" name="ContingentConsiderationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_MeasurementInputProbabilityOfSuccessOfRegulatoryMilestonesMember" abstract="true" name="MeasurementInputProbabilityOfSuccessOfRegulatoryMilestonesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_DirectorsAndExecutiveOfficersPlanTerminationMember" abstract="true" name="DirectorsAndExecutiveOfficersPlanTerminationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="pcrx_DebtInstrumentCovenantLeverageRatioMinimum" abstract="false" name="DebtInstrumentCovenantLeverageRatioMinimum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="pcrx_ConvertibleNotesReceivableMember" abstract="true" name="ConvertibleNotesReceivableMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_AchievementOfDevelopmentAndRegulatoryMilestonesMember" abstract="true" name="AchievementOfDevelopmentAndRegulatoryMilestonesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_ConvertibleSeniorNotesDue2022Member" abstract="true" name="ConvertibleSeniorNotesDue2022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_LongTermInvestmentsMember" abstract="true" name="LongTermInvestmentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_InvestmentCategorizationDomain" abstract="true" name="InvestmentCategorizationDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1: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_ZILRETTAMember" abstract="true" name="ZILRETTAMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <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_ThreeLargestCustomersMember" abstract="true" name="ThreeLargestCustomersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_TermLoanAFacilityDueMarch2028Member" abstract="true" name="TermLoanAFacilityDueMarch2028Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="pcrx_ScheduleOfInterestExpenseTableTextBlock" abstract="false" name="ScheduleOfInterestExpenseTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="pcrx_NumberOfLeases" abstract="false" name="NumberOfLeases" nillable="true" xbrli:periodType="instant" 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-types1:domainItemType"/>
  <xs:element id="pcrx_DebtInstrumentPrepaymentFeePercent" abstract="false" name="DebtInstrumentPrepaymentFeePercent" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="pcrx_DebtInstrumentPercentageOfPrincipalAmountForComputationOfRedemptionPrice" abstract="false" name="DebtInstrumentPercentageOfPrincipalAmountForComputationOfRedemptionPrice" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="pcrx_AchievementOfMilestoneDomain" abstract="true" name="AchievementOfMilestoneDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
</xs:schema>
