By blocking the opioid receptors, naltrexone is believed to reduce the reinforcing effects of alcohol. Recent clinical trials of the medication have used multi-center designs, which permit greater generalization and increased statistical power. There appears to be a much greater risk of hepatotoxicity from chronic excessive alcohol drinking than from treatment with naltrexone at the recommended dosage. For humans, there is a long-acting injection formulated in microspheres that persists for 1 month after a single injection.
The Comprehensive Pharmacology ReferenceTherapeutics Naltrexone is an excellent antagonist of respiratory depression and all the other pharmacological effects of mu opioid agonists such as morphine and heroin. The administration of long-acting naltrexone along with psychosocial support has been associated with improvement in drinking outcome measures, especially among patients who are abstinent entering treatment.
Interventions for AddictionRelated terms: By blocking the mu-opioid receptor, naltrexone acts to decrease the dopamine reward.
Recently, naltrexone has been reported to reduce opiate use in opiate-dependent patients Sullivan et al.
After beginning naltrexone therapy, the risk of overdose death may increase if the patient relapses. Again, naltrexone is an opioid antagonist that blocks the effects of heroin and most other opiates.
Potential contraindications to injectable naltrexone include hemophilia and bleeding problems. Naltrexonethe opioid receptor antagonist discussed earlier, remains the most studied and consistently most effective pharmacotherapy for alcohol dependence [ 39 ].
Naltrexone is then converted to several metabolites.
While not all studies have demonstrated an advantage over placebo, the results of several reviews including two meta-analyses clearly indicate the superiority of naltrexone over placebo in reducing relapse rates to heavy drinking, as well as in other drinking indices.
Naltrexone has also been studied for use in several other medical disorders, including obesity, bulimia, dementia, autism, self-injurious behavior seen in autism, and mental retardation. The naltrexone -treated subjects reported less craving for alcohol at baseline, no change in craving score after the priming dose, drank less alcohol, and reported less alcohol craving overall during the experiment.
If there is a risk of precipitating opioid withdrawal, a naloxone challenge test can be performed. Naltrexone competes for opiate receptors and displaces opioid drugs from these receptors, thus reversing their effects.
Naltrexone blocks the euphorigenic effects of heroin in addicted patients. Collectively, these preclinical findings strongly suggest that naltrexone may have a prominent role in treating cocaine dependence. Compared with oral naltrexoneextended-release naltrexone reduces peak levels and fluctuations in plasma levels to minimize the side effects and elevates trough levels to improve efficacy.
Patients consume less alcohol while receiving naltrexone and those who are sober while receiving treatment tend to have relapses of reduced severity [ 41 ]. Naltrexone and extended-release naltrexone are being evaluated alone and in combination with buprenorphine as a possible pharmacotherapeutic treatment for cocaine dependence.
Please note that Internet Explorer version 8. Naltrexone is an antagonist at the mu, delta, and kappa opioid receptors and was initially investigated for the treatment of opiate dependence.