Breakthrough PainAdministration, BuccalAnalgesics, OpioidFentanylPainLabor PainPain MeasurementNarcoticsAnalgesicsPain ManagementChronic PainAnalgesia, EpiduralPain, PostoperativePain, IntractablePrescription Drug MisuseDouble-Blind MethodNeoplasmsChronic DiseaseNalorphineDrug and Narcotic ControlTreatment OutcomeArthralgiaMedication ErrorsPalliative CareMedication AdherenceNeuralgiaLevorphanolQuestionnairesProspective StudiesMeperidineRetrospective StudiesTime FactorsAnti-Inflammatory Agents, Non-SteroidalPain ThresholdNarcotic AntagonistsLevallorphanLow Back PainSeverity of Illness IndexMorphineRadionuclide GeneratorsAbdominal PainPentazocineBack PainFollow-Up StudiesQuality of LifePatient SatisfactionNeck PainOpiumMedication SystemsComorbidityMedication ReconciliationMedication Systems, HospitalOpioid-Related DisordersCohort StudiesAlphaprodineMorphinansPelvic PainCyclazocineLegislation, DrugPain PerceptionGene DosageMethadoneFacial PainDextropropoxyphene