Breakthrough PainAdministration, BuccalFentanylAnalgesics, OpioidPainLabor PainPain MeasurementAnalgesicsPain ManagementChronic PainAnalgesia, EpiduralPain, PostoperativePain, IntractablePrescription Drug MisuseDouble-Blind MethodNeoplasmsChronic DiseaseMedication AdherenceTreatment OutcomeArthralgiaMedication ErrorsNeuralgiaPalliative CareQuestionnairesProspective StudiesAnti-Inflammatory Agents, Non-SteroidalPain ThresholdTime FactorsRetrospective StudiesRadionuclide GeneratorsSeverity of Illness IndexLow Back PainBack PainPatient SatisfactionQuality of LifeFollow-Up StudiesAbdominal PainNeck PainContraceptives, OralComorbidityMedication SystemsMedication ReconciliationCohort StudiesMedication Systems, HospitalPelvic PainPain PerceptionGene DosageFacial Pain