MethadoneNarcoticsPainOpiate Substitution TreatmentOpioid-Related DisordersHeroin DependenceAnalgesics, OpioidPain ManagementChronic PainMethadyl AcetateBuprenorphinePain ThresholdPain, PostoperativeNeonatal Abstinence SyndromePain, IntractableBack PainHeroinLow Back PainPain MeasurementAbdominal PainNeck PainPelvic PainPain PerceptionFacial PainAcute PainSubstance Abuse DetectionPain, ReferredMorphinePyrrolidinesShoulder PainDrug OverdoseMusculoskeletal PainNarcotic AntagonistsDextropropoxypheneAnalgesicsSubstance Abuse, IntravenousStreet DrugsSubstance-Related DisordersSubstance Withdrawal SyndromeOpiumCocaine-Related DisordersNaloxoneTreatment OutcomeOxidoreductases, N-DemethylatingNociceptive PainStereoisomerismNeuralgiaMeconiumDose-Response Relationship, DrugTherapeutic CommunityCodeineChronic DiseaseDrug InteractionsAnalgesiaDirectly Observed TherapyPrisonersHyperalgesiaHydromorphoneNaltrexone