Analgesics: Compounds capable of relieving pain without the loss of CONSCIOUSNESS.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.Analgesics, Opioid: Compounds with activity like OPIATE ALKALOIDS, acting at OPIOID RECEPTORS. Properties include induction of ANALGESIA or NARCOSIS.Analgesia: Methods of PAIN relief that may be used with or in place of ANALGESICS.Pain: An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.Pain Measurement: Scales, questionnaires, tests, and other methods used to assess pain severity and duration in patients or experimental animals to aid in diagnosis, therapy, and physiological studies.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.Pain, Postoperative: Pain during the period after surgery.Tramadol: A narcotic analgesic proposed for severe pain. It may be habituating.Phenacetin: A phenylacetamide that was formerly used in ANALGESICS but nephropathy and METHEMOGLOBINEMIA led to its withdrawal from the market. (From Smith and Reynard, Textbook of Pharmacology,1991, p431)Acetaminophen: Analgesic antipyretic derivative of acetanilide. It has weak anti-inflammatory properties and is used as a common analgesic, but may cause liver, blood cell, and kidney damage.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.Anti-Inflammatory Agents, Non-Steroidal: Anti-inflammatory agents that are non-steroidal in nature. In addition to anti-inflammatory actions, they have analgesic, antipyretic, and platelet-inhibitory actions.They act by blocking the synthesis of prostaglandins by inhibiting cyclooxygenase, which converts arachidonic acid to cyclic endoperoxides, precursors of prostaglandins. Inhibition of prostaglandin synthesis accounts for their analgesic, antipyretic, and platelet-inhibitory actions; other mechanisms may contribute to their anti-inflammatory effects.Drug Tolerance: Progressive diminution of the susceptibility of a human or animal to the effects of a drug, resulting from its continued administration. It should be differentiated from DRUG RESISTANCE wherein an organism, disease, or tissue fails to respond to the intended effectiveness of a chemical or drug. It should also be differentiated from MAXIMUM TOLERATED DOSE and NO-OBSERVED-ADVERSE-EFFECT LEVEL.Codeine: An opioid analgesic related to MORPHINE but with less potent analgesic properties and mild sedative effects. It also acts centrally to suppress cough.Pain Threshold: Amount of stimulation required before the sensation of pain is experienced.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.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)Pentazocine: The first mixed agonist-antagonist analgesic to be marketed. It is an agonist at the kappa and sigma opioid receptors and has a weak antagonist action at the mu receptor. (From AMA Drug Evaluations Annual, 1991, p97)Pain Management: A form of therapy that employs a coordinated and interdisciplinary approach for easing the suffering and improving the quality of life of those experiencing pain.Receptors, Opioid, mu: A class of opioid receptors recognized by its pharmacological profile. Mu opioid receptors bind, in decreasing order of affinity, endorphins, dynorphins, met-enkephalin, and leu-enkephalin. They have also been shown to be molecular receptors for morphine.Oxycodone: A semisynthetic derivative of CODEINE.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.Dipyrone: A drug that has analgesic, anti-inflammatory, and antipyretic properties. It is the sodium sulfonate of AMINOPYRINE.Hyperalgesia: An increased sensation of pain or discomfort produced by mimimally noxious stimuli due to damage to soft tissue containing NOCICEPTORS or injury to a peripheral nerve.Injections, Spinal: Introduction of therapeutic agents into the spinal region using a needle and syringe.Bupivacaine: A widely used local anesthetic agent.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.Naloxone: A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.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).Carrageenan: A water-soluble extractive mixture of sulfated polysaccharides from RED ALGAE. Chief sources are the Irish moss CHONDRUS CRISPUS (Carrageen), and Gigartina stellata. It is used as a stabilizer, for suspending COCOA in chocolate manufacture, and to clarify BEVERAGES.Ketoprofen: An IBUPROFEN-type anti-inflammatory analgesic and antipyretic. It is used in the treatment of rheumatoid arthritis and osteoarthritis.Kidney Papillary Necrosis: A complication of kidney diseases characterized by cell death involving KIDNEY PAPILLA in the KIDNEY MEDULLA. Damages to this area may hinder the kidney to concentrate urine resulting in POLYURIA. Sloughed off necrotic tissue may block KIDNEY PELVIS or URETER. Necrosis of multiple renal papillae can lead to KIDNEY FAILURE.Tolmetin: A non-steroidal anti-inflammatory agent (ANTI-INFLAMMATORY AGENTS, NON-STEROIDAL) similar in mode of action to INDOMETHACIN.Nefopam: Non-narcotic analgesic chemically similar to ORPHENADRINE. Its mechanism of action is unclear. It is used for the relief of acute and chronic pain. (From Martindale, The Extra Pharmacopoeia, 30th ed, p26)Receptors, Opioid: Cell membrane proteins that bind opioids and trigger intracellular changes which influence the behavior of cells. The endogenous ligands for opioid receptors in mammals include three families of peptides, the enkephalins, endorphins, and dynorphins. The receptor classes include mu, delta, and kappa receptors. Sigma receptors bind several psychoactive substances, including certain opioids, but their endogenous ligands are not known.Hydrocodone: Narcotic analgesic related to CODEINE, but more potent and more addicting by weight. It is used also as cough suppressant.Narcotic Antagonists: Agents inhibiting the effect of narcotics on the central nervous system.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)Pain, Intractable: Persistent pain that is refractory to some or all forms of treatment.Ibuprofen: A nonsteroidal anti-inflammatory agent with analgesic properties used in the therapy of rheumatism and arthritis.Nociception: Sensing of noxious mechanical, thermal or chemical stimuli by NOCICEPTORS. It is the sensory component of visceral and tissue pain (NOCICEPTIVE PAIN).Neuralgia: Intense or aching pain that occurs along the course or distribution of a peripheral or cranial nerve.Hydromorphone: An opioid analgesic made from MORPHINE and used mainly as an analgesic. It has a shorter duration of action than morphine.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Nalorphine: A narcotic antagonist with some agonist properties. It is an antagonist at mu opioid receptors and an agonist at kappa opioid receptors. Given alone it produces a broad spectrum of unpleasant effects and it is considered to be clinically obsolete.Acupuncture Analgesia: Analgesia produced by the insertion of ACUPUNCTURE needles at certain ACUPUNCTURE POINTS on the body. This activates small myelinated nerve fibers in the muscle which transmit impulses to the spinal cord and then activate three centers - the spinal cord, midbrain and pituitary/hypothalamus - to produce analgesia.Cyclohexanecarboxylic AcidsBuprenorphine: A derivative of the opioid alkaloid THEBAINE that is a more potent and longer lasting analgesic than MORPHINE. It appears to act as a partial agonist at mu and kappa opioid receptors and as an antagonist at delta receptors. The lack of delta-agonist activity has been suggested to account for the observation that buprenorphine tolerance may not develop with chronic use.Edema: Abnormal fluid accumulation in TISSUES or body cavities. Most cases of edema are present under the SKIN in SUBCUTANEOUS TISSUE.Nociceptors: Peripheral AFFERENT NEURONS which are sensitive to injuries or pain, usually caused by extreme thermal exposures, mechanical forces, or other noxious stimuli. Their cell bodies reside in the DORSAL ROOT GANGLIA. Their peripheral terminals (NERVE ENDINGS) innervate target tissues and transduce noxious stimuli via axons to the CENTRAL NERVOUS SYSTEM.Diclofenac: A non-steroidal anti-inflammatory agent (NSAID) with antipyretic and analgesic actions. It is primarily available as the sodium salt.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.Butorphanol: A synthetic morphinan analgesic with narcotic antagonist action. It is used in the management of severe pain.Oxymorphone: An opioid analgesic with actions and uses similar to those of MORPHINE, apart from an absence of cough suppressant activity. It is used in the treatment of moderate to severe pain, including pain in obstetrics. It may also be used as an adjunct to anesthesia. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1092)