Naltrexone is a medication primarily approved for treating alcohol and opioid use disorders. The search for effective pharmacological treatments for cocaine use disorder is ongoing, and researchers have explored naltrexone as a potential supportive treatment, although more studies are needed to confirm its effectiveness. Cocaine addiction is characterized by compulsive use despite harmful consequences, and it directly affects the brain’s reward system.
The Scientific Rationale for Using Naltrexone
Naltrexone functions as an opioid receptor antagonist, meaning it blocks the effects of opioid drugs. Its potential application for cocaine use disorder stems from the relationship between the brain’s dopamine and opioid systems. Cocaine primarily increases dopamine levels in the brain’s reward pathway, leading to the intense euphoria and reinforcing properties of the drug.
The scientific hypothesis is that the brain’s own endogenous opioid system is interconnected with this dopamine-driven reward circuitry. By binding to and blocking opioid receptors, naltrexone is thought to indirectly modulate the dopamine system. This blockade may dampen the rewarding feelings experienced from cocaine use, which could, in turn, help to reduce cravings and the motivation to use the drug.
Using naltrexone for cocaine dependence is considered an “off-label” application, as the U.S. Food and Drug Administration (FDA) has not specifically approved it for this purpose. Its use is based on the theoretical neurobiological connection and the search for treatments for a condition that currently has no FDA-approved medications.
Clinical Evidence on Efficacy
The body of research examining naltrexone’s effectiveness for cocaine use disorder has produced mixed results. There is no simple consensus on whether it is a consistently effective treatment, and its impact appears to vary among different populations of individuals.
Some clinical trials have suggested that naltrexone may be more beneficial for individuals who have a co-occurring alcohol use disorder. Relapse to cocaine use is often triggered by alcohol consumption, and since naltrexone is approved for alcohol dependence, its mechanism may indirectly help reduce cocaine use in this specific subgroup by addressing the alcohol component. One study that tested high-dose naltrexone in people dependent on both cocaine and alcohol found it did not reduce cocaine use but did decrease the frequency of heavy drinking days.
Conversely, other studies have found limited or no significant effect of naltrexone on reducing cocaine use, particularly in individuals without a concurrent alcohol dependence. Research has shown that even at higher doses, naltrexone did not consistently affect cocaine use, and any positive effects reported were often short-lived. The collective findings have been described as “less than robust,” indicating the clinical evidence does not yet definitively establish its effectiveness as a widespread treatment for cocaine use disorder alone.
Administration and Potential Side Effects
Naltrexone is administered in two forms. The first is an oral tablet, taken once daily. The other is a long-acting, extended-release intramuscular injection administered once a month, which can be an alternative for individuals who have difficulty with daily medication adherence.
Like many medications, naltrexone is associated with a range of potential side effects. The most common ones include nausea, headache, dizziness, and anxiety. These effects are often mild and may decrease as the body adjusts to the medication.
There are also more serious risks that require careful consideration before starting treatment. Naltrexone carries a risk of liver damage, and it is contraindicated for individuals with acute hepatitis or liver failure. A significant danger is the increased risk of opioid overdose for individuals who relapse on opioids. Because naltrexone blocks opioid receptors, a person might not feel the effects of a typical dose of opioids and may take a much larger amount, leading to a potentially fatal overdose when the naltrexone wears off. For this reason, it must not be used by anyone currently taking opioids.
Naltrexone’s Role in a Comprehensive Treatment Plan
Naltrexone is not a standalone cure but is a form of medication-assisted treatment (MAT), meaning it functions as one component of a broader recovery program. The medication can help manage the biological aspects of addiction, but long-term recovery depends on addressing psychological and social factors as well.
For the greatest chance of success, naltrexone should be integrated with various forms of behavioral therapy and support. Therapies such as Cognitive Behavioral Therapy (CBT) help individuals identify and change the thought patterns and behaviors that contribute to substance use. Professional counseling and peer support groups also provide a foundation for building coping skills and a strong support network.
While a medication like naltrexone may help reduce cravings or the rewarding effects of a substance, the behavioral and therapeutic elements of a treatment plan are what equip individuals with the tools they need for sustained recovery. The medication can provide a period of stability that allows a person to more fully engage with and benefit from these other forms of therapy.