Breakthrough PainAdministration, BuccalFentanylAnalgesics, OpioidPainAnorexia NervosaAnorexiaLabor PainPain MeasurementAnalgesicsPain ManagementChronic PainAnalgesia, EpiduralPain, PostoperativePain, IntractablePrescription Drug MisuseDouble-Blind MethodNeoplasmsChronic DiseaseTreatment OutcomeArthralgiaMedication ErrorsMedication AdherencePalliative CareNeuralgiaQuestionnairesProspective StudiesAnti-Inflammatory Agents, Non-SteroidalPain ThresholdTime FactorsRetrospective StudiesRadionuclide GeneratorsSeverity of Illness IndexLow Back PainBack PainQuality of LifeFollow-Up StudiesPatient SatisfactionAbdominal PainComorbidityNeck PainMedication ReconciliationMedication SystemsMedication Systems, HospitalCohort StudiesPelvic PainPain PerceptionFacial Pain