NarcoticsAnalgesicsAnalgesics, OpioidNalorphineDrug and Narcotic ControlAnalgesics, Non-NarcoticNarcotic AntagonistsMorphineLevorphanolMeperidinePentazocineAnalgesiaPainLevallorphanPain MeasurementPain, PostoperativeDextropropoxypheneMorphinansCyclazocineFentanylCodeineOpiumDose-Response Relationship, DrugAlphaprodineOxymorphoneDrug ToleranceOpioid-Related DisordersLegislation, DrugHormone AntagonistsMethadoneTramadolOxycodoneReceptors, Opioid, muExcitatory Amino Acid AntagonistsAcetaminophenNeurokinin-1 Receptor AntagonistsHydrocodoneDopamine AntagonistsReceptors, OpioidRats, Sprague-DawleyHeroinPhenacetinHistamine H2 AntagonistsPreanesthetic MedicationPiperidinesPain ManagementNaltrexoneInterleukin 1 Receptor Antagonist ProteinMuscarinic AntagonistsHydromorphonePain, IntractableNaloxoneAnesthetics, LocalAnti-Inflammatory Agents, Non-SteroidalGABA AntagonistsTime FactorsBupivacaineHistamine H1 AntagonistsDouble-Blind MethodButorphanolPurinergic P1 Receptor AntagonistsNicotinic AntagonistsMorphine DerivativesPain ThresholdHistamine AntagonistsSubstance-Related DisordersRats, WistarAlfentanilSpasmDrug InteractionsBuprenorphineAnalgesia, Patient-ControlledHyperalgesiaAdrenergic alpha-1 Receptor AntagonistsInjections, SpinalEndorphinsAdenosine A2 Receptor AntagonistsMorphine DependencePurinergic P2 Receptor AntagonistsAnesthesiaMethotrimeprazineSubstance Withdrawal SyndromeInert Gas NarcosisSerotonin 5-HT3 Receptor AntagonistsNitrous OxideSerotonin 5-HT2 Receptor AntagonistsAdrenergic alpha-2 Receptor AntagonistsHypnotics and SedativesDibenzocycloheptenesTreatment OutcomeIsonipecotic AcidsAlcoholics AnonymousAdenosine A1 Receptor AntagonistsAdrenergic alpha-AntagonistsLeukotriene AntagonistsAngiotensin Receptor AntagonistsMitragynaBridged CompoundsDipyroneEnkephalins