MorphineNarcoticsMorphine DependenceMorphine DerivativesAnalgesics, OpioidNalorphineDrug and Narcotic ControlNarcotic AntagonistsLevorphanolDrug ToleranceMeperidineLevallorphanPentazocineNaloxoneCodeineOpiumMorphinansPain, PostoperativeAnalgesicsReceptors, Opioid, muFentanylAnalgesiaCyclazocineHeroinPain MeasurementOxymorphoneAlphaprodineMethadoneSubstance Withdrawal SyndromeOpioid-Related DisordersPainDextropropoxypheneLegislation, DrugOxycodoneHydromorphoneReceptors, OpioidInjections, SpinalNaltrexonePreanesthetic MedicationAnalgesia, Patient-ControlledHydrocodoneDose-Response Relationship, DrugPapaverPain, IntractableEnkephalinsSubstance-Related DisordersEndorphinsSpasmMethadyl AcetateInert Gas NarcosisButorphanolMethotrimeprazineAlcoholics AnonymousAlfentanilBuprenorphineEnkephalin, Ala(2)-MePhe(4)-Gly(5)-Periaqueductal GrayAnesthesiaRats, Sprague-DawleyBupivacaineMitragynaIsonipecotic AcidsDrug InteractionsNalbuphineNeonatal Abstinence SyndromeInfusion PumpsTime FactorsDibenzocycloheptenesAnesthetics, LocalReceptors, Opioid, deltaAnalgesics, Non-NarcoticKetonesParamethasoneHeroin DependenceBridged CompoundsDrug OverdosePain ManagementStreet DrugsSubstance Abuse DetectionPharmacyThebainePerphenazineNitrous OxideDouble-Blind MethodPain ThresholdAnalgesia, EpiduralBehavior, AnimalPalliative CareBrainFuransPhenanthrenesNerve BlockDrug Administration ScheduleReceptors, Opioid, kappaInjections, SubcutaneousSpinal CordAnestheticsDoping in SportsHypnotics and SedativesGastrointestinal Diseases