The FDA ( U.S: Food and Drug Administration ) has approved a monthly injectable formulation of Vivitrol ( Naltrexone for extended-release ) for treatment of alcohol-dependent patients.

Naltrexone works by binding to opioid receptors in the brain.
Although the mechanism responsible for the reduction in alcohol consumption observed with Naltrexone treatment is not entirely understood, preclinical data suggests that occupation of the opioid receptors results in the blockade of the neurotransmitters in the brain that are believed to be involved with alcohol dependence. This blockade may result in the reduction in alcohol consumption observed in patients treated with Vivitrol.

In a six-month phase III trial, patients treated with Naltrexone ( 380 mg ) and psychosocial support demonstrated a reduction in days of heavy drinking compared with patients treated with placebo and psychosocial support.

In a subset of patients who were abstinent for a week before starting Vivitrol treatment, the drug was associated with continued abstinence in a significant number of patients.
Moreover, patients who were abstinent before receiving the initial injection of Vivitrol had a greater reduction in drinking days and heavy-drinking days.

Although Vivitrol was generally well tolerated, with the most common side effects being nausea, vomiting, headache, fatigue, and injection site rejections, high doses of Naltrexone have been reported to cause hepatocellular injury.

The drug is contraindicated in patients with acute hepatitis or liver failure, and its "use in patients with active liver disease must be carefully considered in light of its hepatotoxic effects."

Vivitrol is contraindicated in patients receiving opioid analgesics. Likewise, it contraindicated in opioid-dependent patients and patients undergoing opioid withdrawal.

Alcohol dependence is a chronic disease with underlying neurological and genetic factors.
The four symptoms most commonly associated with alcohol dependence are cravings, loss of control over drinking, withdrawal symptoms ( including sweating, nausea, shakiness and anxiety ) and an increased tolerance for alcohol.

Source: Cephalon, 2006


XagenaMedicine2006