AnalgesicsAnalgesics, OpioidMorphineNarcoticsReceptors, Opioid, muPainEtorphinePain MeasurementNaloxoneAnalgesics, Non-NarcoticNalorphineAnalgesiaDrug and Narcotic ControlPain, PostoperativeMeperidineLevorphanolPentazocineDextropropoxypheneNarcotic AntagonistsLevallorphanTramadolCodeineFentanylPhenacetinAcetaminophenMorphinansDrug ToleranceCyclazocineOxycodoneOpiumOxymorphoneAlphaprodineOpioid-Related DisordersPain ManagementHydrocodoneAnti-Inflammatory Agents, Non-SteroidalMethadoneAnesthetics, LocalLegislation, DrugPain ThresholdHydromorphonePain, IntractableBupivacaineAnalgesia, Patient-ControlledReceptors, OpioidPreanesthetic MedicationHeroinDipyroneHyperalgesiaDouble-Blind MethodInjections, SpinalButorphanolBuprenorphineAlfentanilMorphine DerivativesDose-Response Relationship, DrugAnalgesia, EpiduralCarrageenanKetoprofenEndorphinsKidney Papillary NecrosisNitrous OxideTolmetinHypnotics and SedativesNefopamKetorolacIbuprofenSubstance-Related DisordersNerve BlockNociceptionNeuralgiaNaltrexoneMethotrimeprazineAcupuncture AnalgesiaSpasmCyclohexanecarboxylic AcidsMorphine DependenceEdemaTime FactorsDiclofenacTreatment OutcomeNociceptorsDrug OverdoseAnesthesiaAnalgesia, ObstetricalMeptazinolInert Gas NarcosisAnestheticsNociceptive PainAntipyreticsKetamineAcetic AcidMitragynaPapaverNalbuphineSubstance Withdrawal SyndromeEnkephalinsAlcoholics AnonymousAcute PainRats, Sprague-Dawley