Acute PainPainAnalgesics, OpioidPain MeasurementPain ManagementPain, PostoperativePain ClinicsChronic PainPain ThresholdAnalgesicsAnalgesiaPain, IntractableMorphineHyperalgesiaPain PerceptionNarcotic AntagonistsAnesthesia Department, HospitalLow Back PainBack PainFacial PainNeuralgiaAcute DiseaseNaloxoneAnalgesics, Non-NarcoticNarcoticsAnalgesia, Patient-ControlledOpioid-Related DisordersAbdominal PainNeck PainNociceptorsPelvic PainUnited States Department of DefenseOxycodoneInjections, SpinalOpioid PeptidesReceptors, OpioidEnkephalin, MethionineChronic DiseaseBuprenorphineFentanylPain, ReferredRecovery RoomEnkephalin, Ala(2)-MePhe(4)-Gly(5)-Isotonic SolutionsAnalgesia, EpiduralAnesthetics, LocalAcupunctureShoulder PainNociceptive PainCyclohexanecarboxylic AcidsMusculoskeletal PainReceptors, Opioid, kappaAminooxyacetic AcidEndorphinsEnkephalinsHydromorphoneKetoprofenKetorolacKetamineSpinal CordAnti-Inflammatory Agents, Non-SteroidalAcetaminophenFormaldehydeTreatment OutcomeDiclofenacDouble-Blind MethodCryingRats, Sprague-DawleyDose-Response Relationship, DrugBehavior, AnimalReceptors, Opioid, deltaLidocaineGanglia, SpinalCapsaicinCuldoscopyPrescription DrugsAlfentanilPeripheral Nervous System DiseasesEnkephalin, D-Penicillamine (2,5)-OxymorphoneSkin Physiological PhenomenaPosterior Horn CellsAnesthetics, DissociativeTranscutaneous Electric Nerve StimulationAnesthesiologyNerve BlockQuestionnairesAminesTime FactorsDynorphinsDexmedetomidineHerpes ZosterDrug Tolerancebeta-EndorphinTramadolCodeineAnemia, Sickle CellPrescription Drug MisuseProspective StudiesCarrageenan