A drug originally developed for the treatment of depression may be effective for treating acute opioid withdrawal symptoms and preventing relapse in opioid addicts.
A recent study revealed that the experimental drug rapastinel—which failed to show positive effects on depression in clinical trials—significantly reversed symptoms of withdrawal in opioid-dependent rats in just three days.
Currently, buprenorphine (Subutex, Suboxone) and methadone are the most commonly used drugs to treat opioid withdrawal, with ketamine being the third most common. However, buprenorphine and methadone are problematic because they are also opioids and pose the risk of addiction, as well as having to be administered for months in order for an addict to possibly avoid relapse.
For the study, researchers modeled opioid dependence in three groups of rats, each administered rapastinel, ketamine or a saline solution. On day three, the rats given rapastinel exhibited substantially fewer signs of withdrawal than those in the ketamine and saline groups, which showed roughly equal amounts of symptoms. These research findings indicate that ketamine is ineffective in treating acute opioid withdrawal.
Rapastinel for Acute Opioid Withdrawal
These findings are a promising development for addicts who seek treatment for withdrawal, largely because of the severity of symptoms during early recovery. It is in the first few days of abstinence that addicts face the most difficult withdrawal symptoms, including intense cravings due to both physical dependence and mental suffering that too often cause them to return to opioids for relief.
Safe and Effective Alternative
Due to rapastinel's fast-acting efficacy for relieving symptoms in the most critical stage of withdrawal, it may serve as a safe and effective alternative to treating opioid addicts with other opioids (buprenorphine and methadone) or a heavy sedative (ketamine), thus reducing the need for addicts in treatment to be subjected to the dangerous side effects that these drugs cause.
Although rapastinel binds to the same receptor as ketamine, it binds to a different site and has a milder effect. In addition, although rapastinel failed as an effective antidepressant in clinical trials with humans, it was well tolerated by participants and caused no serious side effects.
Because of rapastinel’s success in alleviating early withdrawal symptoms in rats, researchers will move forward in studying its effects on a molecular level and investigate whether or not rapastinel reduces the likelihood of relapse.
According to researcher Julia Ferrante, "Rapastinel research for opioid dependency is currently only being done in rodents, but if the drug continues to have successful trials, it may enter clinical trials for use in humans." Ferrante is an undergraduate at Villanova University and conducted the study with Cynthia M. Kuhn, PhD, professor of pharmacology and cancer biology at Duke University.
If the drug is approved for the treatment of opioid withdrawal, it will most likely be administered intravenously in either an inpatient or outpatient setting, or both. At this point, it is unknown how long addicts would need rapastinel in order to fully recover from dependence.
With more research on the horizon and the possibility of human trials and approval of rapastinel for opioid dependence, there may be hope for the drug to enhance recovery for addicts and lessen the growing opioid crisis.