Breakthrough PainAdministration, BuccalFentanylAnalgesics, OpioidPainLabor PainPain MeasurementAnalgesicsPain ManagementChronic PainAnalgesia, EpiduralPain, PostoperativePain, IntractablePrescription Drug MisuseDouble-Blind MethodNeoplasmsChronic DiseaseArthralgiaTreatment OutcomeMedication ErrorsMedication AdherenceNeuralgiaPalliative CareQuestionnairesProspective StudiesAnti-Inflammatory Agents, Non-SteroidalPain ThresholdRadionuclide GeneratorsRetrospective StudiesLow Back PainBack PainTime FactorsSeverity of Illness IndexQuality of LifePatient SatisfactionFollow-Up StudiesAbdominal PainNeck PainComorbidityMedication ReconciliationMedication SystemsMedication Systems, HospitalCohort StudiesPelvic PainPain PerceptionFacial Pain