Meperidine: A narcotic analgesic that can be used for the relief of most types of moderate to severe pain, including postoperative pain and the pain of labor. Prolonged use may lead to dependence of the morphine type; withdrawal symptoms appear more rapidly than with morphine and are of shorter duration.Shivering: Involuntary contraction or twitching of the muscles. It is a physiologic method of heat production in man and other mammals.Analgesics, Opioid: Compounds with activity like OPIATE ALKALOIDS, acting at OPIOID RECEPTORS. Properties include induction of ANALGESIA or NARCOSIS.Adjuvants, Anesthesia: Agents that are administered in association with anesthetics to increase effectiveness, improve delivery, or decrease required dosage.Analgesia, Obstetrical: The elimination of PAIN, without the loss of CONSCIOUSNESS, during OBSTETRIC LABOR; OBSTETRIC DELIVERY; or the POSTPARTUM PERIOD, usually through the administration of ANALGESICS.Promethazine: A phenothiazine derivative with histamine H1-blocking, antimuscarinic, and sedative properties. It is used as an antiallergic, in pruritus, for motion sickness and sedation, and also in animals.Hydroxyzine: A histamine H1 receptor antagonist that is effective in the treatment of chronic urticaria, dermatitis, and histamine-mediated pruritus. Unlike its major metabolite CETIRIZINE, it does cause drowsiness. It is also effective as an antiemetic, for relief of anxiety and tension, and as a sedative.Dihydroergotamine: A 9,10alpha-dihydro derivative of ERGOTAMINE. It is used as a vasoconstrictor, specifically for the therapy of MIGRAINE DISORDERS.Alfentanil: A short-acting opioid anesthetic and analgesic derivative of FENTANYL. It produces an early peak analgesic effect and fast recovery of consciousness. Alfentanil is effective as an anesthetic during surgery, for supplementation of analgesia during surgical procedures, and as an analgesic for critically ill patients.Analgesia, Epidural: The relief of pain without loss of consciousness through the introduction of an analgesic agent into the epidural space of the vertebral canal. It is differentiated from ANESTHESIA, EPIDURAL which refers to the state of insensitivity to sensation.Conscious Sedation: A drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway. (From: American Society of Anesthesiologists Practice Guidelines)Preanesthetic Medication: Drugs administered before an anesthetic to decrease a patient's anxiety and control the effects of that anesthetic.Fentanyl: A potent narcotic analgesic, abuse of which leads to habituation or addiction. It is primarily a mu-opioid agonist. Fentanyl is also used as an adjunct to general anesthetics, and as an anesthetic for induction and maintenance. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1078)Chloral Hydrate: A hypnotic and sedative used in the treatment of INSOMNIA.Cesarean Section: Extraction of the FETUS by means of abdominal HYSTEROTOMY.Analgesia, Patient-Controlled: Relief of PAIN, without loss of CONSCIOUSNESS, through ANALGESIC AGENTS administered by the patients. It has been used successfully to control POSTOPERATIVE PAIN, during OBSTETRIC LABOR, after BURNS, and in TERMINAL CARE. The choice of agent, dose, and lockout interval greatly influence effectiveness. The potential for overdose can be minimized by combining small bolus doses with a mandatory interval between successive doses (lockout interval).Butorphanol: A synthetic morphinan analgesic with narcotic antagonist action. It is used in the management of severe pain.Dextropropoxyphene: A narcotic analgesic structurally related to METHADONE. Only the dextro-isomer has an analgesic effect; the levo-isomer appears to exert an antitussive effect.Ketorolac Tromethamine: A pyrrolizine carboxylic acid derivative structurally related to INDOMETHACIN. It is a non-steroidal anti-inflammatory agent used for analgesia for postoperative pain and inhibits cyclooxygenase activity.Morphine: The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.Sufentanil: An opioid analgesic that is used as an adjunct in anesthesia, in balanced anesthesia, and as a primary anesthetic agent.Anesthesia, Spinal: Procedure in which an anesthetic is injected directly into the spinal cord.Ketorolac: A pyrrolizine carboxylic acid derivative structurally related to INDOMETHACIN. It is an NSAID and is used principally for its analgesic activity. (From Martindale The Extra Pharmacopoeia, 31st ed)Serotonin Syndrome: An adverse drug interaction characterized by altered mental status, autonomic dysfunction, and neuromuscular abnormalities. It is most frequently caused by use of both serotonin reuptake inhibitors and monoamine oxidase inhibitors, leading to excess serotonin availability in the CNS at the serotonin 1A receptor.Skin Temperature: The TEMPERATURE at the outer surface of the body.Analgesics, Non-Narcotic: A subclass of analgesic agents that typically do not bind to OPIOID RECEPTORS and are not addictive. Many non-narcotic analgesics are offered as NONPRESCRIPTION DRUGS.Anesthesia, Dental: A range of methods used to reduce pain and anxiety during dental procedures.Tolmetin: A non-steroidal anti-inflammatory agent (ANTI-INFLAMMATORY AGENTS, NON-STEROIDAL) similar in mode of action to INDOMETHACIN.Anesthetics, Local: Drugs that block nerve conduction when applied locally to nerve tissue in appropriate concentrations. They act on any part of the nervous system and on every type of nerve fiber. In contact with a nerve trunk, these anesthetics can cause both sensory and motor paralysis in the innervated area. Their action is completely reversible. (From Gilman AG, et. al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed) Nearly all local anesthetics act by reducing the tendency of voltage-dependent sodium channels to activate.