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 ThresholdRetrospective StudiesRadionuclide GeneratorsTime FactorsLow Back PainBack PainSeverity of Illness IndexQuality of LifePatient SatisfactionFollow-Up StudiesAbdominal PainNeck PainMedication SystemsComorbidityMedication ReconciliationMedication Systems, HospitalCohort StudiesPelvic PainPain PerceptionGene DosageFacial Pain