Analgesics, OpioidAspirinAcetaminophenPainAnalgesicsPain MeasurementAnalgesics, Non-NarcoticPain ManagementReceptors, Opioid, muChronic PainPain, PostoperativeReceptors, OpioidPrescription Drug MisuseReceptors, Opioid, deltaPain, IntractableAnti-Inflammatory Agents, Non-SteroidalReceptors, Opioid, kappaDrug OverdoseOpioid PeptidesArthralgiaTreatment OutcomeMedication AdherenceMedication ErrorsNeuralgiaPalliative CareDextropropoxypheneProspective StudiesPain ThresholdDrug PackagingQuestionnairesNarcotic AntagonistsTime FactorsIbuprofenLow Back PainOpioid-Related DisordersSeverity of Illness IndexBack PainRetrospective StudiesNaloxoneMorphinePatient SatisfactionPlatelet Aggregation InhibitorsFollow-Up StudiesQuality of LifeAcute PainNaltrexoneCodeineCohort StudiesDouble-Blind MethodAbdominal PainComorbidityFacial PainNeck PainAntidotesNarcoticsPoisoningMedication ReconciliationMedication SystemsAntipyreticsMedication Systems, HospitalSalicylatesDrug-Induced Liver InjuryPain PerceptionPelvic PainBuprenorphineAnalgesiaDrug Therapy, CombinationPrescription DrugsEnkephalinsEnkephalin, Ala(2)-MePhe(4)-Gly(5)-Dose-Response Relationship, DrugCharcoalDrug PrescriptionsSelf MedicationPain, ReferredDrug InteractionsDiclofenacSuppositoriesNonprescription DrugsEnkephalin, D-Penicillamine (2,5)-EndorphinsDrug UtilizationDynorphinsPatient ComplianceCyclooxygenase InhibitorsDrug Administration ScheduleShoulder PainDipyroneRisk FactorsChronic DiseaseMusculoskeletal PainTooth ExtractionAdministration, OralTiclopidineTramadolGastric LavageEnkephalin, LeucineFeverMolar, ThirdTablets