Pill helps addicts forget marijuana

The drug gabapentin, already on the market to treat neuropathic pain and epilepsy, quiets the brain circuitry responsible for withdrawal symptoms in marijuana addicts.

Marijuana hooks users by altering stress circuits in their brains. People can get reliant on using pot to deal with stress, and then once off of it their stress symptoms can rebound excessively. Barbara J. Mason of the Scripps Research Institute explains in a press release:

"In human cannabis users who try to quit, this stress response is reflected in reports of drug craving, sleep disturbances, anxiety, irritability, and dysphoria, any one of which can motivate a person to return to using, because cannabis will quiet these symptoms."

So far, there aren't any FDA-approved drug therapies for cannabis dependence. But hold up, you may be thinking, is marijuana actually addictive? Mason says yes:

"Some people deny that cannabis can be addictive, but surveys show that between 16 and 25 percent of substance use treatment admissions around the world every year involve people with primary cannabis dependence."

A 2008 study had found that gabapentin, a frequently prescribed anticonvulsant drug, can quiet withdrawal-related stress circuitry activation in alcohol-dependent rats (don't ask). Gabapentin resembles the neurotransmitter GABA, which regulates neuronal excitability in the central nervous system. Since cannabis withdrawal features a similar over-activation of stress circuits as alcohol withdrawal, Mason decided to test gabapentin on marijuana addicts.

She recruited 50 marijuana users who hoped to quit the drug. Half of the subjects took 1,200 mg/day of gabapentin, the other 25 took a placebo pill. Mason monitored the subjects over twelve weeks.

Her results, published in the journal Neuropsychopharmacology, show that the gabapentin subjects had much higher success at staying off marijuana. Mason details in the press release:

"Urine metabolite readings indicate about twice as many of the gabapentin subjects had no new cannabis use during the entire study, and, in the last four weeks of the study, all of the gabapentin subjects who completed the study stayed abstinent."

Gabapentin reduced symptoms of withdrawal. Its use resulted in fewer sleep disturbances, less drug cravings, less unhappiness, and even some evidence of sharpened cognition.

Mason explains why she thinks gabapentin works for treating marijuana withdrawal:

"That weakening of self-control-related circuits makes it even harder for people to resist drug cravings when they’re trying to quit, but gabapentin may help restore those circuits, by reducing stress and enabling patients to sleep better, so that they function better while awake."

Mason's now conducting a larger study to confirm gabapentin's success in helping people quit cannabis use. The drug is already approved by the FDA (for neuropathic pain and epilepsy), but prescribing it to marijuana addicts would be an "off-label use." Which means its manufacturers can't advertise gabapentin as a therapy for the symptoms of marijuana withdrawal, but doctors can legally prescribe it to patients trying to quit.

Photo: r0bz/Flickr

This post was originally published on Smartplanet.com