BuprenorphineMorphineNarcotic AntagonistsOpioid-Related DisordersAnalgesics, OpioidNarcoticsMorphine DependenceMorphine DerivativesNaloxoneOpiate Substitution TreatmentMorphinansMethadoneAdministration, SublingualReceptors, Opioid, muHeroin DependenceDrug ToleranceSubstance Withdrawal SyndromeNaltrexoneReceptors, OpioidHeroinAnalgesiaMethadyl AcetatePain MeasurementNeonatal Abstinence SyndromeAnalgesicsCodeinePain, PostoperativeDose-Response Relationship, DrugHydromorphoneNalbuphineInjections, SpinalLevorphanolPainSubstance Abuse DetectionFentanylOpiate AlkaloidsDrug InteractionsNalorphineReceptors, Opioid, deltaDouble-Blind MethodReceptors, Opioid, kappaTramadolThiazinesRats, Sprague-DawleyDiprenorphineOxycodoneEnkephalin, Ala(2)-MePhe(4)-Gly(5)-MeperidineButorphanolDrug CombinationsPentazocinePrescription Drug DiversionPrescription Drug MisuseStreet DrugsCyclazocineSubstance Abuse Treatment CentersOpioid PeptidesDrug and Narcotic ControlOpiumPain ThresholdEnkephalinsPain, IntractableEtorphineAnalgesia, Patient-ControlledBehavior, AnimalEthylketocyclazocine