REHAB is indicated in the treatment of alcohol dependence and for the blockade of the effects of exogenously administered opioids.
Mode of Action
The mechanism of action of REHAB in alcoholism is not understood. It is thought to act as a competitive antagonist at mc, κ, and δ receptors in the CNS, with the highest affinity for the µ receptor. REHAB competitively binds to such receptors and may block the effects of endogenous opioids. This leads to the antagonization of most of the subjective and objective effects of endogenous opiates, including respiratory depression, meiosis, euphoria, and drug craving.
Although well absorbed orally, REHAB is subject to significant first pass metabolism with oral bioavailability estimates ranging from 5 to 40%. 21% bound to plasma proteins. Metabolism- Hepatic. When administered orally, REHAB undergoes extensive biotransformation and is metabolized to 6 beta-naltrexol (which may contribute to the therapeutic effect) and other minor metabolites. About the route of elimination, both parent drug and metabolites are excreted primarily by the kidney (53% to 79% of the dose).The renal clearance for REHAB ranges from 30 to 127 mL/min. Half-life is 4 hours for REHAB and 13 hours for the active metabolite 6 beta-naltrexol.
Dosage and Recommendation
Treatment should not be attempted unless the patient has remained free of opioids for at least 7 to 10 days. Opioid abstinence should be verified by analysis of urine for absence of opioids. For opioids withdrawal patients: Initial dose: 25 mg orally one time. Maintenance dose: if no withdrawal signs occur, 5omg orally once a day may be started. Alternative dose schedules: (to improve compliance) 50 mg orally on week days and 100 mg orally on Saturday; or 100 mg orally every other day; or 150 mg orally every third day. No dose adjustment is required in patients with mild renal dysfunction and mild or moderate liver dysfunction.
Packing and Presentation
Available dose is 50mg tablet. Each strip contains 10 tablets.