HydrocodoneHydromorphoneOxycodoneCodeineOxymorphoneObstetric Surgical ProceduresAnalgesics, OpioidPainSubstance Abuse DetectionMorphine DerivativesAntitussive AgentsNarcoticsMiosisCytochrome P-450 CYP2D6Gas Chromatography-Mass SpectrometryAcetaminophenPain, PostoperativeOpioid-Related DisordersChronic PainPain ManagementMorphine