Naltrexone is a medication used to help individuals manage cravings and reduce relapse in certain substance use disorders. It supports recovery by addressing the physiological aspects of addiction, making it a valuable tool in a broader treatment strategy. It is not a cure, but an aid to help individuals maintain sobriety or reduce substance use. It is a prescription drug approved for specific conditions to assist in recovery.
How Naltrexone Works
Naltrexone functions as an opioid receptor antagonist, blocking opioid effects in the brain. It competitively binds to opioid receptors, particularly mu-opioid receptors, responsible for the pleasurable effects of opioid and alcohol consumption. By occupying these receptors, naltrexone prevents external opioids (such as heroin or prescription pain relievers) from binding and producing euphoric or pain-relieving effects. This blockade also extends to the body’s naturally produced opioids, known as endorphins.
Alcohol consumption can stimulate the release of these endogenous opioids, contributing to its rewarding effects. By blocking mu-opioid receptors, naltrexone diminishes the pleasurable “high” or “buzz” from alcohol or opioids. This reduces the desire or craving for these substances over time. Naltrexone itself does not produce opioid-like effects and is not considered addictive. It modulates the brain’s reward pathway, reducing cravings and supporting an opioid-free or alcohol-reduced state.
Addictions Naltrexone Addresses
Naltrexone is approved for treating two primary substance use disorders: alcohol use disorder and opioid use disorder. For alcohol use disorder, naltrexone reduces cravings and diminishes the rewarding effects of drinking. It can decrease the frequency of drinking, the total amount consumed, and the number of heavy drinking days. This mechanism helps individuals either abstain from alcohol or reduce their consumption, preventing a “slip” from turning into a full relapse.
For opioid use disorder, naltrexone blocks the euphoric and sedative effects of opioids. If an individual uses an opioid while on naltrexone, they will not experience the desired “high.” This helps reduce cravings and prevent relapse for those who have already stopped opioid use. Naltrexone is a non-opioid medication, making it a distinct treatment option.
How Naltrexone is Administered
Naltrexone is available as an oral tablet and an extended-release injectable suspension. The oral tablet is typically taken once daily, often at 50 milligrams (mg) for alcohol use disorder. For opioid use disorder, a starting dose of 25 mg may be used for a day, potentially increasing to 50 mg daily if no withdrawal symptoms occur. Taking the oral tablet with or after meals can help minimize gastrointestinal side effects.
The extended-release injectable form is administered as an intramuscular injection, typically into the gluteal area, once a month. This formulation delivers 380 mg of naltrexone continuously over the dosing interval, which can improve treatment adherence. The injection must be prepared and administered by a healthcare professional. Both forms aim to maintain a consistent medication level in the body to effectively block opioid receptors.
Important Considerations for Naltrexone Use
Before starting naltrexone, individuals must be completely opioid-free for 7 to 14 days to prevent severe precipitated withdrawal. Precipitated withdrawal occurs when naltrexone rapidly displaces opioids from receptors, causing immediate, intense, and highly unpleasant withdrawal symptoms. Symptoms include nausea, vomiting, chills, and abdominal pain. Healthcare providers often perform tests, such as a urine screen, to confirm opioid abstinence.
Common side effects include nausea, headache, dizziness, and stomach pain. For the injectable form, injection site reactions like pain, swelling, or hardness can occur. While rare, serious side effects like liver damage or hepatitis have been reported, so liver function monitoring may be necessary.
Naltrexone is most effective as part of a comprehensive treatment plan including counseling, therapy, and psychosocial support. Individuals must inform healthcare providers about all medications they are taking, as naltrexone can block the effects of opioid-containing medicines used for pain relief, cough, or diarrhea. Attempting to overcome naltrexone’s blockade by taking large doses of opioids is extremely dangerous and may lead to serious injury, overdose, or death due to reduced opioid tolerance.