Sunday, October 24, 2010

A New/Old Treatment for Opiate Addiction

Gov makes naltrexone legit for heroin.

Last week, the government officially sanctioned the use of naltrexone, trade name Vivitrol, for use in the treatment of heroin addiction. Approved years ago by the FDA for use in the treatment of alcoholism, naltrexone is a long-acting opiate receptor antagonist that has been widely used for heroin detoxification, withdrawal, and maintenance for some time. In that light, the official approval was a bit of an anticlimax, and of less scientific interest than naltrexone’s earlier approval for alcohol dependence. 

While naltrexone has yet to become the huge treatment breakthrough for alcoholism that addiction researchers hoped for it, naltrexone did, in the end, prove to be the first anti-craving medication widely available for alcoholics. Using an opiate antagonist as an aid to the prevention of alcoholic relapse would have been unthinkable without the underpinnings of a neurophysiological model of addiction. Various investigators have also speculated that naltrexone, the drug used as an adjunct of heroin withdrawal therapy, may find use against symptoms of marijuana withdrawal in people prone to marijuana dependence

Naltrexone has something of a mixed reputation, however, in part due to its use in the highly controversial practice of “rapid detox.” Naltrexone, like methadone and buprenorphine, blocks the heroin high in a relatively neutral manner. It does so by knocking the opiate molecule off its receptors and replacing it with “dead weight,” so to speak. Naltrexone would seem to be the perfect drug for heroin addicts—but it is not. It does little to reduce cravings. Like acamprosate for alcohol, another blocking approach, its record of accomplishment is mixed, and the dropout rate is high. There is not even a mild drug-like effect to provide cross-tolerance and dampen the effects of withdrawal, as with methadone. Recently, naltrexone for heroin addiction has been offered as a form of rapid detoxification. The addict is anesthetized and placed on a respirator, then injected with naltrexone. The result: complete detoxification in a matter of hours, as the naltrexone molecules knock the opium molecules off their receptors. It can be lethal if not carefully controlled and supervised. The problem, as always, is that the detoxified addict is just as vulnerable to heroin addiction as before. Rapid detox does nothing to combat subsequent cravings, and relapse is frequent.

 Naltrexone combined with buprenorphine is marketed as Subutex, and represents another treatment modality for opiate addiction.  In addition, a University of Minnesota study of kleptomania—the compulsion to steal—showed that naltrexone drastically reduced stealing among a group of 25 shoplifters.

Naltrexone will be offered as a monthly injection, an approach that has not been widely tested on opiate addicts, but is potentially an advantage over frequent visits to methadone clinics or daily ingestion of other treatment drugs. Unfortunately, naltrexone is a potential problem for people with liver disease or hepatitis.  At high doses, naltrexone has been implicated in liver damage. More common adverse effects include dizziness, lethargy, and headache.

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Mike Lisieski said...

I was under the impression that withdrawal from opiates (antagonist-precipitated or not) was unpleasant, but not deadly. While naltrexone could have other toxicities, I believe you are wrong when you say that naltrexone-precipated withdrawal can itself be deadly (assuming, of coures, that it doesn't also prompt self-harming behaviors from the addict.) Is there something I'm missing - a reason why it would be more dangerous than, say, naloxone-precipated withdrawal or spontaneous withdrawal?

Dirk Hanson said...

Hi Mike:

Different rapid detox systems use different drug combinations, but there have been fatalities associated with the procedure:

LANSING,MI - Attorney General Mike Cox announced that the medical licenses of Robert A. Wolf, M.D., and Aeneas Guiney, M.D., have been summarily suspended by the Board of Medicine following the deaths of two patients and the hospitalizations of three others placed in their care. Doctors Wolf and Guiney were medical partners at Project Straight, a rapid detoxification center for opioid addicts that was located in Troy. The company offered a detoxification procedure that involved first administering anesthesia to patients and then administering medications in order to flush opioids out of their systems.

Charles Somer said...

Never mind licensing naltrexone for heroin withdrawal. What about licensing it for use in alcoholism, not as an aid to withdrawal rather as in the so-called Sinclair method. At the moment the FDA has only approved its use in patients who have ceased drinking. It's time to move away from the abstinent model( or at least give people an option) -AA has a five year success rate of 5%, which is pitiful- and try new treatments for a disease that kills far, far more people than heroin addiction, and that tears families and communities apart. The Sinclair method which is used widely in Finland has a three year success rate of 90%. What is going on?

Tom at Recovery Helpdesk said...

As pointed out in the post, naltrexone is already used to treat opiate dependence. But in my experience, usefulness of the treatment is limited by the fact that many patients simply skip doses or stop taking the medication as part of a relapse to opiate use.

The interesting twist offered by Vivitrol is that a single dose of Vivitrol is active for one month limiting the temptation and opportunity to circumvent the treatment.

Jen said...

You mentioned Subutex which is an alternative treatment option but Subutex does not contain Naltrexone. It's only active ingredient is buprenorphine.

Dirk Hanson said...

Jen--You are correct. My error. It should read: "Naltrexone combined with buprenorphine (Subutex), represents another treatment modality..."

The Pharm Hand said...

Naltrexone and buprenorphine are combined in the new detox or maintenance drug "Suboxone". In this rural part of Virginia, where methadone clinics don't exist, it is the only chemical option assisted detox or maintenance. As a semi-reformed former junkie, who took suboxone for many months, I thought it to be a miracle drug at first but eventually found it as difficult to get away from as methadone. I basically had to return to real opiates for a period of time (2 weeks is the conventional wisdom) and then wean myself off the morphine (much easier). Suboxone is very commonly diverted by addicts in treatment, who sell it to other addicts as a cheap substitute for heroin or oxycontin, which the diverting addict can then afford. Suboxone prices on the black market in Virginia range from $12-20, the average prescription is for 60-90 tablets/month. I know people who are as addicted to their daily crumb of "stopsigns" (Suboxones are octagonal) as any other junkie, and the withdrawal period being so scarily long, they are loathe to consider quitting. I believe it has something to do with the very long half-life of the buprenorphine.

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