Naltrexone¿¡ ´ëÇÑ Mechanism_Of_Action Á¤º¸ Naltrexone binds to the opioid mu receptor antagonistically, thereby preventing conventional opiate (heroin, morphine) drugs from binding and inducing opioid neural responses. The mechanism of action of naltrexone in alcoholism is not understood; however, involvement of the endogenous opioid system is suggested by preclinical data. Naltrexone competitively binds to such receptors and may block the effects of endogenous opioids.
Pharmacology
Naltrexone¿¡ ´ëÇÑ Pharmacology Á¤º¸ Naltrexone, a pure opioid antagonist, is a synthetic congener of oxymorphone with no opioid agonist properties. Naltrexone is indicated in the treatment of alcohol dependence and for the blockade of the effects of exogenously administered opioids. It markedly attenuates or completely blocks, reversibly, the subjective effects of intravenously administered opioids. When co-administered with morphine, on a chronic basis, naltrexone blocks the physical dependence to morphine, heroin and other opioids. In subjects physically dependent on opioids, naltrexone will precipitate withdrawal symptomatology.
Protein Binding
Naltrexone¿¡ ´ëÇÑ ´Ü¹é°áÇÕ Á¤º¸ 21% bound to plasma proteins over the therapeutic dose range.
Half-life
Naltrexone¿¡ ´ëÇÑ ¹Ý°¨±â Á¤º¸ 4 hours for naltrexone and 13 hours for the active metabolite 6 beta-naltrexol.
Absorption
Naltrexone¿¡ ´ëÇÑ Absorption Á¤º¸ Although well absorbed orally, naltrexone is subject to significant first pass metabolism with oral bioavailability estimates ranging from 5 to 40%.
Naltrexone¿¡ ´ëÇÑ Biotransformation Á¤º¸ Hepatic. When administered orally, naltrexone undergoes extensive biotransformation and is metabolized to 6 beta-naltrexol (which may contribute to the therapeutic effect) and other minor metabolites.
Toxicity
Naltrexone¿¡ ´ëÇÑ Toxicity Á¤º¸ In the mouse, rat and guinea pig, the oral LD50s were 1,100-1,550 mg/kg; 1,450 mg/kg; and 1,490 mg/kg; respectively. High doses of naltrexone (generally ¡Ã1,000 mg/kg) produce salivation, depression/reduced activity, tremors, and convulsions.
Drug Interactions
Naltrexone¿¡ ´ëÇÑ Drug_Interactions Á¤º¸ Alfentanil Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsBuprenorphine Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsCodeine Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsDihydrocodeine Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsFentanyl Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsHeroin Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsHydrocodone Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsHydromorphone Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsLevorphanol Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsMeperidine Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsMethadone Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsMorphine Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsNalbuphine Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsSufentanil Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsPropoxyphene Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsPentazocine Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsOxymorphone Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individualsOxycodone Naltrexone may precipitate a withdrawal syndrome in opioid-dependent individuals
Naltrexone¿¡ ´ëÇÑ Description Á¤º¸ Derivative of noroxymorphone that is the N-cyclopropylmethyl congener of naloxone. It is a narcotic antagonist that is effective orally, longer lasting and more potent than naloxone, and has been proposed for the treatment of heroin addiction. The FDA has approved naltrexone for the treatment of alcohol dependence. [PubChem]
The database contains the following fields: The generic name of each chemical For module A10 (liver enzyme composite module): Overall activity category for each compound (A for active, M for marginally active, or I for inactive) based on the number of active and marginally active scores for each compound at the five individual endpoints (see research article for full description of method) Number of endpoints at which each compound is marginally active (M) Number of endpoints at which each compound is active (A) For modules A11 to A15 (alkaline phosphatase increased, SGOT increased, SGPT increased, LDH increased, and GGT increased, respectively): Overall activity category for each compound (A for active, M for marginally active, or I for inactive) based on the RI and ADR values (see the research article for full description of method) Number of ADR reports for each compound, given as <4 or ¡Ã4 Reporting Index value for each compound, except where no shipping units were available (NSU) Group 1 comprises of compounds for which ADR data were available for the first five years of marketing, so when no ADR reports were listed during this period the compounds were evaluated as inactive. Group 2 comprises of compounds for which a 'steady state' period of ADR data were available (1992-1996). In cases where no ADR reports were filed during this period, the compounds were scored as 'NA' (data not available) since they may have had one or more ADR reports during their first five years of marketing which should not be negated by a lack of ADR reports during the steady-state period. NALTREXONE [GGT Increase] [Composite Activity] (Score)I (Marginal) 0 (Active) 0