AnalgesiaAnalgesia, EpiduralAnalgesia, ObstetricalAnalgesia, Patient-ControlledPlacebo EffectAnalgesics, OpioidDouble-Blind MethodPain, PostoperativePain MeasurementMorphineBupivacaineAnesthetics, LocalAcupuncture AnalgesiaFentanylAnalgesicsPainAnesthesia, EpiduralMeperidineLabor PainSufentanilNerve BlockInjections, SpinalLabor, ObstetricAnesthesia, ObstetricalAmidesTramadolAnalgesics, Non-NarcoticAnesthesia, SpinalTreatment OutcomeCross-Over StudiesNaloxonePain ThresholdPostoperative Nausea and VomitingCesarean SectionInterpleural AnalgesiaLidocaineReceptors, Opioid, muDose-Response Relationship, DrugPain ManagementDrug ToleranceConscious SedationHydromorphoneClonidineHypnotics and SedativesLabor Stage, FirstAnesthesia, GeneralKetorolacKetamineDrug Administration ScheduleProspective StudiesAnesthesia, CaudalPregnancyNarcotic AntagonistsAnesthesia and AnalgesiaFemoral NerveReceptors, OpioidAlfentanilPirinitramideKetoprofenDrug Therapy, CombinationPruritusTime FactorsAnti-Inflammatory Agents, Non-SteroidalButorphanolNalbuphineAnesthetics, CombinedAdministration, OralPiperidinesOpioid PeptidesAnesthesia, ConductionAdjuvants, AnesthesiaThoracotomyElectroacupunctureMepivacaineAnesthesia, LocalInfusions, IntravenousSingle-Blind MethodAcetaminophenHyperalgesiaMorphine DerivativesInjections, IntravenousPostoperative CareRandomized Controlled Trials as TopicNitrous OxidePentazocineOxycodoneHysterectomyDexmedetomidineAmbulatory Surgical ProceduresPeriaqueductal GrayDrug CombinationsPrilocainePain, IntractablePain PerceptionClinical Trials as TopicInjections, EpiduralPreanesthetic MedicationAnesthetics, DissociativeBrachial PlexusCodeine