The questions that come up most often when people are starting naltrexone, taking it, or trying to decide whether to. Each answer is short and points to a longer article if there’s one. This article is part of our Naltrexone hub, the complete guide to using naltrexone for alcohol use disorder.
If your question isn’t here, the pillar article covers the topic at length.
# Starting out
# 1. What is naltrexone?
A medication that blocks mu-opioid receptors in the brain. When you drink alcohol while it’s active, the dopamine reward you’d normally get is partially or fully blocked. Used for alcohol use disorder and opioid use disorder. Generic since 2013.
# 2. How does it actually work for alcohol?
Two main protocols. Daily: 50mg every day, reduces overall drinking. The Sinclair Method (TSM): 50mg an hour before each drinking session, used to gradually extinguish the urge to drink over months. We cover the mechanism in The Sinclair Method Explained.
# 3. Will it stop me from drinking?
No. Naltrexone reduces the reward of drinking; it doesn’t make you unable to drink. You can still drink while taking it. The drinking just becomes less rewarding over time, which gradually reduces the urge.
# 4. How is it different from Antabuse (disulfiram)?
Antabuse makes you sick if you drink. Naltrexone makes drinking less rewarding. Different mechanisms, different goals. Antabuse is for patients committed to abstinence; naltrexone is for patients reducing or considering reducing. We compare them in Naltrexone vs Acamprosate vs Disulfiram.
# 5. How do I get a prescription?
Talk to your GP, an addiction specialist, or a telemedicine service. Be specific about what you want. Country-specific routes in How to Get a Naltrexone Prescription.
# Dosing
# 6. What’s the standard dose?
50mg once daily for daily protocols, or 50mg about an hour before drinking for TSM. Some prescribers start at 25mg for the first 1-2 weeks to ease side effects, then increase to 50mg.
# 7. What’s the “one hour rule”?
For TSM specifically: take the tablet roughly one hour before your first drink. The medication needs that time to dissolve, absorb, and saturate the receptors before alcohol arrives. Forty-five minutes to two hours is fine. Fifteen minutes is not. See Naltrexone Dosing.
# 8. Can I take more than 50mg?
Doses up to 100-150mg have been studied but the benefit plateaus around 50mg while side effects increase. For long sessions (8+ hours), a second 50mg dose 6-8 hours after the first is standard. Don’t routinely take more than 100mg/day.
# 9. What if I forget to take it?
For daily protocols, take it as soon as you remember if it’s still the same day. If close to bedtime, skip and resume tomorrow. For TSM, taking it after you’ve already started drinking provides partial coverage for subsequent drinks; not ideal but not useless.
# 10. Can I take it on an empty stomach?
Yes, but with food reduces nausea, especially in the first weeks. Slight delay in peak absorption (about 30 minutes) but no meaningful loss of effect.
# Side effects
# 11. What side effects should I expect?
Most common: nausea, headache, fatigue, vivid dreams. Most resolve within 1-3 weeks. Less common: dizziness, anxiety, joint pain, decreased appetite. Rare: liver enzyme elevations. See Naltrexone Side Effects for what’s normal.
# 12. How long does the nausea last?
Typically 1-2 weeks for daily naltrexone, sometimes a few hours after each TSM dose for the first month. Taking it with food and starting at 25mg can substantially reduce it.
# 13. What about my liver?
At 50mg, naltrexone causes mild reversible liver enzyme elevations in a small minority of patients. Most prescribers do baseline LFTs and recheck at 3-6 months. Severe liver disease (acute hepatitis, decompensated cirrhosis) is a true contraindication; mild-moderate liver disease is not.
# 14. Will it affect my mood?
Some patients report mild dysphoria or emotional flattening, especially in the first weeks. Usually transient. If persistent, worth discussing with your prescriber. Naltrexone affects opioid pathways involved in pleasure response generally, not just alcohol-specific pleasure.
# 15. Can it cause weight loss?
Indirectly yes, mostly via alcohol-calorie reduction. Direct weight-loss effect on its own is small. We cover the connection in Naltrexone and Weight Loss.
# Drinking on naltrexone
# 16. Will I still feel drunk?
Yes, somewhat. Naltrexone doesn’t block alcohol’s intoxicating effects (slurring, coordination, judgment). It blocks the reward signal that makes you want another drink. You can still get drunk; the experience is just less reinforcing.
# 17. Will alcohol still taste the same?
Yes. Naltrexone doesn’t affect taste. The change is in how rewarding the drink feels rather than how it tastes.
# 18. Can I get drunk faster on naltrexone?
No. Blood alcohol concentration rises the same way. The intoxication itself is unchanged.
# 19. What about hangovers?
Naltrexone doesn’t directly affect hangovers. Whatever physiological reaction you get to alcohol the next morning is unchanged. However, since most patients drink less on naltrexone over time, hangovers naturally reduce alongside reduced consumption.
# 20. Can I drink heavily while on naltrexone?
You can, but the protocol’s behavioural effect comes from the dose-drink reward suppression. Drinking heavily without naltrexone doses (forgetting on TSM) means you’re reinforcing drinking unmedicated, which slows the protocol.
# 21. Should I be drinking on naltrexone?
For TSM, yes: that’s how the extinction works. For daily protocols, drinking less is the goal; drinking heavily anyway means the medication isn’t doing its job.
# Daily life
# 22. Can I drive on naltrexone?
Yes, no driving restrictions associated with naltrexone itself. If you’re drinking while taking it, the alcohol has the same effect on your driving as without naltrexone.
# 23. Can I exercise on naltrexone?
Yes. Some patients report a slight initial reduction in exercise enjoyment (the runner’s-high opioid reward is mildly blunted), but most don’t notice and the effect typically fades within weeks.
# 24. Can I have sex on naltrexone?
Yes. A minority of patients report mildly reduced libido or harder-to-achieve orgasm in early use; usually transient. Worth discussing with your prescriber if persistent.
# 25. Will I need to tell employers, insurers, etc.?
Naltrexone doesn’t appear on standard employment drug screens. Insurance disclosure depends on jurisdiction and policy type. Generally treated like any other prescription medication.
# 26. What if I need surgery or pain medication?
This is critical. Naltrexone blocks the receptors that opioid pain medications work on. If you need elective surgery, stop naltrexone 72 hours before. For emergency pain, tell the medical team you’re on naltrexone immediately so they can plan accordingly. Wear a medical ID if possible. Tramadol, codeine, and other “weak” opioids are also affected.
# 27. Can I take it with antidepressants?
Generally yes. SSRIs (sertraline, fluoxetine, etc.), SNRIs (venlafaxine, duloxetine), bupropion, and most other antidepressants have no significant interaction with naltrexone. Always confirm with your prescriber for your specific combination.
# Edge cases
# 28. What if I’m on opioid maintenance therapy (buprenorphine, methadone)?
Naltrexone is incompatible with opioid agonist therapy. The combination triggers acute withdrawal. If transitioning from buprenorphine or methadone to naltrexone, full opioid washout (typically 7-10 days for buprenorphine, longer for methadone) is required first under medical supervision.
# 29. How long should I stay on it?
For daily naltrexone, typical course is 3-6 months minimum, often longer if it’s helping. For TSM, the protocol is designed for indefinite use, though many patients eventually stabilise at lower drinking levels and reduce or stop. There’s no fixed endpoint.
# 30. What happens when I stop?
Naltrexone clears the system in 3-5 days. The receptors return to baseline. Whatever drinking pattern you’ve trained during your time on naltrexone is what remains. For TSM patients with good extinction, the underlying urge to drink is much lower. For daily-naltrexone patients, the urge typically returns to its prior level relatively quickly.
# How AlcoLog supports your treatment
AlcoLog’s Medications card has a dedicated naltrexone entry. Each dose gets a timestamp via the 24-hour time picker. The redose timer (set in hours + minutes) reminds you when a long session needs a second tablet. The last-24h dose list shows what you’ve taken at a glance.
Pro-tier location reminders fire when you arrive at saved locations: useful for the Sinclair Method where you want the tablet timed to drinking events.
AlcoScore deliberately excludes medication use from its scoring. The app’s view: medication is a tool you choose to use, not a behaviour the app should grade you on. Your dose log informs you, not your score. Data stays on your device. CSV export of your last 10 sessions is free; unlimited export and PDF reports are on Pro for sharing with your prescriber.
