Vivitrol is a new drug approved for use in the management of opiate addiction. It was approved in the US for treating alcohol dependency in 2006 and opiate addiction in October 2010. The active agent in Vivitrol is naltrexone, an opioid receptor antagonist. Naltrexone is a long-lasting opioid receptor antagonist, and this makes it suitable for helping addicts overcome their opiate addiction. It is not a narcotic, and it has no addictive potential. Vivitrol is the injectable form of naltrexone, and the drug molecule is made into an extended-release formulation.
How does it work?
Vivitrol or naltrexone occupies and blocks the opioid receptors in the brain. Because it is an antagonist at these receptors, it elicits no psychotropic effects; therefore, addicts feel no euphoria, no rush, and no psychogenic effects. Should addicts try take opiates while on naltrexone, they get no positive effects at all and are even likely to get sick. The lack of psychotropic response to opiates during naltrexone therapy provides a strong guard against addicts relapsing.
How is it used?
Vivitrol is given as an intramuscular injection once a month. The extended-release formulation supplies the body regularly with the appropriate doses of naltrexone and provides a deterrent cover for 30 days.
What are its merits?
Naltrexone or Vivitrol represents a significant milestone in the treatment of drug addiction and in addressing the public health menace that is opiate abuse. Often, a drug succeeds mostly on its perception among the population and the compliance of the patients on it. Vivitrol is a great improvement over methadone and suboxone in these areas.
First, Vivitrol is non-narcotic. Methadone and buprenorphine in suboxone are synthetic opioids and agonists of opioid receptors in the brain. This means that they produce opiate-like effects even though these are milder. Methadone and buprenorphine are highly regulated drugs because of their addictive potential. The naltrexone in Vivitrol, on the other hand, shows no addictive potential. This makes Vivitrol safe for long-term use with the fear of patients developing a fast dependence on it.
Secondly, Vivitrol is given once monthly and by intramuscular injections. Methadone and suboxone are given daily. Methadone administration needs close monitoring and daily visits to methadone clinics. Vivitrol, on the other hand, requires only one visit per month and no specific clinic staff to administer it. These promote compliance among addicts and encourage them to complete their recovery.
Similarly, since Vivitrol is delivered by injection, there is no doubt that patients are taking it. It is possible for relapsing addicts to cheat on their methadone or suboxone dosages but nearly impossible with Vivitrol.
What are its demerits?
No drug is without its side effects and certainly not Vivitrol. It can cause nausea, vomiting, dizziness, fatigue, cramps, muscle aches, loss of appetite, rashes, swelling, depression, and liver damage.
There is also the arguable fact that naltrexone can cause withdrawal symptoms and cravings. Since it is purely an opioid antagonist, it provides no opiate-like effect to condition the addict. Some experts argue that these subdued cravings and withdrawal symptoms may become big deterrents in certain patients, even though they are not for most patients.
Lastly, long-term use of an antagonist can sensitize the receptors towards the agonist. In this case, long-term Vivitrol therapy can make the opioid receptors in the brain too sensitive to opiates and synthetic opioids for some periods after the therapy. This can lead to opioid overdose even with safe doses of opioids given immediately after Vivitrol therapy.