Why Trust Recovery Guide When taking naltrexone for opioid and alcohol addiction, it’s helpful to understand how quickly it works and how long its effects last. Naltrexone typically starts working within one to two hours of a standard dose, though exactly when depends on which form is taken. The pill form tends to kick in within about an hour, while the injectable form (Vivitrol) takes closer to two hours to reach its initial effects.
As an opioid antagonist, naltrexone blocks the effects of opioids and alcohol fairly quickly after that first dose, making it an effective option for many people in recovery from either condition.
How Many Hours Does Naltrexone Work?
Naltrexone is prescribed in the form of a pill or extended-release injection. In pill form, naltrexone effects can last between 24 to 48 hours, depending on the dose taken.
Extended-release naltrexone injections (Vivitrol) for opioid addiction produce effects slowly over the course of a one-month period. How long effects last may vary according to some factors.
Factors that can affect the duration of effects include:
- Age: Older adults metabolize drugs at a slower rate, which may cause the drug to stay in a person’s system for longer.
- Metabolic Rate: A slow rate of metabolism can cause naltrexone to stay in the body for longer and thus prolong its effects.
- Use of Other Drugs: Certain medications can interact with naltrexone and cause it to metabolize at a slower rate or reduce its effects.
- Body Mass: Body weight can affect the rate of drug absorption and how long it takes for the body to fully process drugs like naltrexone.
Naltrexone is generally taken either once a day, or three times a week in pill form. The injectable form of naltrexone is administered once a month by a licensed healthcare provider.
What To Know About The Effects Of Naltrexone
Naltrexone should be taken exactly as prescribed by the prescribing physician. People taking naltrexone should avoid drinking alcohol, using illicit drugs, or taking medications known to have negative drug interactions with naltrexone.
Taking naltrexone in ways other than directed could result in:
- reduced drug effects
- drug toxicity
- accidental overdose
- other adverse reactions
Certain drugs may enhance or reduce the effects of naltrexone. If you’re taking other medication, be sure to tell your doctor before beginning naltrexone treatment.
Can You Build A Tolerance To Naltrexone?
Unlike opioids or many other addictive substances, naltrexone doesn’t cause a person to build tolerance over time. Since it’s not an opioid itself and doesn’t activate the brain’s reward system the way addictive drugs do, the body doesn’t adapt to it in the same way, meaning the same dose should continue working effectively throughout the addiction treatment process.
This is one of the reasons naltrexone is considered a safer long-term option for many people in recovery. There’s no need to continually increase the dose to maintain its effects, and stopping the medication won’t cause withdrawal symptoms the way stopping opioids or certain other medications might.