Naltrexone is a medication used to treat alcohol use disorder. A common question is whether it can cause alcohol withdrawal. Naltrexone does not induce alcohol withdrawal; it works through a different mechanism entirely and does not produce the physiological effects that lead to withdrawal symptoms.
What Naltrexone Is
Naltrexone is a medication primarily prescribed for alcohol use disorder and, in some cases, opioid use disorder. It is not an opioid itself and does not create dependence. It comes as an oral pill taken daily or an extended-release injectable form administered monthly.
Naltrexone is a tool within a broader treatment plan. It helps individuals reduce heavy drinking days and maintain abstinence by modifying the brain’s response to alcohol, rather than acting as a substitute.
How Naltrexone Affects the Body
Naltrexone functions as an opioid antagonist, blocking the effects of opioid chemicals in the brain. When alcohol is consumed, it triggers the release of endorphins, natural opioid-like chemicals produced by the body. These endorphins bind to opioid receptors, contributing to the pleasurable feelings associated with drinking.
Naltrexone occupies these same opioid receptors, preventing endorphins from binding. This reduces or eliminates alcohol’s euphoric effects, diminishing cravings and the desire to drink. Naltrexone modulates reward pathways; it does not interfere with the neurochemical processes that cause alcohol withdrawal.
Naltrexone and Drinking Alcohol
When a person consumes alcohol while taking naltrexone, they do not experience the usual pleasurable or rewarding effects. Naltrexone blocks the endorphin-mediated “buzz” or euphoria that many people seek. Individuals might still feel negative physical effects like nausea, dizziness, or impaired coordination, but without the desired psychological reward.
This is the body’s reaction to alcohol consumption without opioid-mediated reinforcement, not alcohol withdrawal. The absence of the rewarding sensation can make drinking less appealing and help reduce overall alcohol intake. Naltrexone does not interfere with the brain’s adaptation to chronic alcohol exposure, so it does not cause true alcohol withdrawal symptoms.
What Alcohol Withdrawal Is
Alcohol withdrawal syndrome occurs when a person with physical dependence on alcohol suddenly stops or significantly reduces intake. Prolonged, heavy alcohol consumption alters brain chemistry, leading to rebound overactivity of neurotransmitters when alcohol is absent. This hyperexcitability of the central nervous system manifests as withdrawal symptoms.
Symptoms range from mild to severe, typically beginning 6 to 24 hours after the last drink. Common symptoms include tremors, anxiety, nausea, vomiting, headache, and insomnia. Severe cases may involve hallucinations, seizures, or delirium tremens, a medical emergency characterized by confusion, rapid heart rate, and fever. These symptoms result from the body adapting to alcohol’s absence.
Key Considerations for Naltrexone
Medical supervision is important when starting and continuing naltrexone treatment. A healthcare provider determines the appropriate dosage and monitors for any side effects. Common side effects, distinct from withdrawal symptoms, include nausea, headache, dizziness, or fatigue. These are usually mild and often diminish over time.
Individuals should be free of opioids for at least 7 to 10 days before starting naltrexone, especially the injectable form. This prevents precipitated opioid withdrawal, which can occur if naltrexone blocks opioid receptors in someone with physical opioid dependence. Additionally, naltrexone should not be initiated during acute alcohol withdrawal, as it does not treat these symptoms.