New Medication Options for Treating Cocaine Addiction
Doctors and researchers have long looked for a medication capable of easing the effects of cocaine addiction. For a variety of reasons, their past efforts haven’t been successful, and there is no single medication on the market capable of filling this role. However, current evidence indicates that two other medications-buprenorphine and naltrexone-that were initially designed for other purposes, apparently work in combination to ease cocaine addiction and facilitate successful participation in cocaine rehab programs. Doctors usually use buprenorphine to treat opioid addiction, while naltrexone is used to treat both opioid and alcohol addiction.
Cocaine is a stimulant drug that produces euphoria by increasing levels of dopamine, a neurotransmitting chemical found in the brain’s pleasure centers (known to scientists as the limbic system). Normally, dopamine is only used to relay short-term pleasure signals between the neurons within the limbic system; once dopamine molecules perform their jobs, they get broken down and recycled for later use. Cocaine molecules effectively block the dopamine recycling process and trigger an abnormal buildup of the chemical.
When any given person first starts using cocaine, the drug consistently boosts dopamine levels and triggers significant euphoria. However, over time, the brain will adjust to repeated use of the drug by lowering its dopamine output; in turn, this lowered dopamine output will decrease the amount of pleasure experienced by a cocaine user. Typically, the road to addiction begins when any given user starts to increase his or her intake of the drug in hopes of recreating the initial experience of euphoria.
While doctors use buprenorphine to treat opioid addiction, the medication itself is an opioid drug. However, when compared to opioid drugs of abuse such as oxycodone and heroin, it produces relatively minor levels of euphoria within the body. When a person already addicted to stronger opioids takes buprenorphine, its less intense effect gradually reduces the user’s level of drug dependence, while simultaneously helping to eliminate the harsh side effects associated with drug withdrawal. At the same time, buprenorphine blocks certain types of chemical activity in the brain that normally increase addicts’ desire to use more drugs.
In chemical terms, naltrexone is an opioid receptor antagonist. This means that it blocks the neuron receptors in the body that normally respond to the effects of opioid drugs; in turn, this blocking action prevents opioids from triggering addiction-promoting euphoria. Doctors can use the drug to help prevent relapses in recovering opioid addicts. In recovering alcoholics, naltrexone helps reduce the persistence of alcohol cravings, although no one knows quite how it achieves this effect.
Usefulness in Treating Cocaine Addiction
Many people with opioid addictions also use cocaine. In the early 2000s, some doctors and researchers started noticing that cocaine-using opioid addicts significantly decreased their level of cocaine intake when they received buprenorphine as part of their opioid recovery programs. A follow-up study, published in 2012 in the journal Science Translational Medicine, confirmed buprenorphine’s ability to reduce cocaine intake and potentially play a vital role in treating cocaine addiction. However, as noted previously, buprenorphine is an opioid drug. While it can help ease opioid addiction in people who already use opioid drugs, it can also easily trigger opioid addiction in people who don’t use opioid drugs. In practical treatment terms, doctors and researchers faced a dilemma: How do you safely use buprenorphine to treat cocaine addiction in people who are not already addicted to opioid drugs?
That’s where naltrexone comes in. As we noted previously, this drug acts as an opioid receptor antagonist and blocks opioid drugs from triggering addiction-promoting levels of euphoria inside the body. This means that, in people who receive buprenorphine as a treatment for cocaine addiction, naltrexone can prevent the onset of unintended (and clearly unwanted) opioid addiction. However, in order to achieve the proper blend of effects, doctors must carefully control the amount of naltrexone they prescribe. This is true because, in its role as an opioid receptor antagonist, naltrexone can easily cancel out buprenorphine’s effects entirely when used in relatively large doses.
As of 2013, work on the combined use of buprenorphine and naltrexone as a cocaine addiction treatment is preliminary, and current findings come from animal studies, not human studies. Still, officials from the National Institute on Drug Abuse believe this medication combination holds clear promise as an effective treatment in human populations. The authors of the study published in Science Translational Medicine believe that a buprenorphine/naltrexone combination could also potentially help treat additional health problems such as depression, schizophrenia, obsessive-compulsive disorder and chronic pain syndrome.