Vivitrol and oral naltrexone are the same molecule delivered three different ways. Oral naltrexone is a daily tablet. Vivitrol is a monthly intramuscular injection. Naltrexone implants are a less common option used mostly outside the US. The drug’s mechanism doesn’t change between formats; what changes is adherence, cost, and how the medication fits into daily life. This article is part of our Naltrexone hub, the complete guide to using naltrexone for alcohol use disorder.
The choice between formats is rarely about efficacy and almost always about practical fit. This article walks through what each format actually involves, the cost gap, who tends to do better on which, and the case for implants where they’re available.
# The molecule is the same
All three formats contain naltrexone, a mu-opioid receptor antagonist. The pharmacology is identical:
- Blocks opioid receptors so alcohol’s reward pathway is blunted
- Half-life of naltrexone itself is around 4 hours, with the active metabolite (6-beta-naltrexol) at around 13 hours
- Effective for daily protocols, the Sinclair Method, and post-detox relapse prevention
What differs across formats is purely how the drug gets into your bloodstream over time.
# Oral naltrexone
Format: 50mg tablet taken once daily (for daily protocols) or about an hour before drinking (for TSM).
How long it lasts: Effective for about 24 hours per dose, with peak coverage between 2-12 hours after taking.
Adherence pattern: Daily, requiring you to remember every day for daily protocols, or to remember the one-hour window for TSM. Real-world adherence to daily naltrexone is roughly 50-60% across studies. Many patients miss doses without realising the cumulative effect on their treatment.
Cost: Generic, very cheap. £10-25/month UK private, $4-50/month US (much cheaper with GoodRx-style discount cards), AUD $40-80/month Australia (heavily discounted with PBS).
Suits: Self-motivated patients comfortable with a daily routine. Patients on TSM specifically (Vivitrol cannot do TSM because the drug is constantly in your system; the targeted-dosing mechanism doesn’t apply). Patients still figuring out whether the medication suits them; cheap and easy to discontinue if it doesn’t.
Doesn’t suit: Patients with adherence challenges, especially those whose drinking pattern includes impulsive bingeing where they might “forget” to take the tablet on a heavy day.
# Vivitrol (monthly intramuscular injection)
Format: 380mg of extended-release naltrexone in microspheres, injected into the gluteal muscle every four weeks. Injection itself takes 1-2 minutes; you walk out of the clinic immediately.
How long it lasts: Continuous receptor blockade for 28-30 days, peaking around day 2-3 and gradually declining toward day 30. By design, you stay covered between scheduled injections.
Adherence pattern: One decision per month. Either you turn up to the appointment or you don’t. Studies of Vivitrol consistently show better real-world outcomes than oral naltrexone, mostly because the adherence problem is removed.
Side effects: Same as oral naltrexone (nausea, headache, fatigue) plus injection-site reactions (soreness, redness, occasional infection). The injection-site reactions are rare and usually mild.
Cost: Much higher than oral. Around $1,500 per shot before insurance in the US (so $1,500/month, $18,000/year). Fully covered by Medicaid and Medicare in most US states for alcohol use disorder treatment. In the UK, Vivitrol is not licensed for alcohol use disorder (though approved for opioid use disorder); access through the NHS for alcohol is rare. In Australia, it’s available through some specialist clinics but not commonly used for alcohol.
Suits: Patients who have struggled with oral naltrexone adherence. Patients in supervised treatment programs where the once-monthly model fits well. Patients with strong commitment to staying sober but who don’t want to think about medication daily. Patients who can access insurance coverage; the cash price is prohibitive for most.
Doesn’t suit: Patients on TSM (the constant blockade defeats the targeted-dosing mechanism). Patients who want to test naltrexone briefly before committing; oral is much more flexible. Patients without insurance coverage or other access route. Patients afraid of injections.
# Naltrexone implants
Format: A subcutaneous implant placed under the skin (typically in the abdomen or hip), delivering naltrexone over 3-6 months from a single procedure. Implants are not FDA-approved in the US and are not commonly available in the UK or Australia. They’re used primarily in Russia, parts of Europe, parts of Australia (off-label), and at some private clinics globally.
How long it lasts: Variable. Different products claim 2-month, 3-month, 6-month, or 12-month coverage. Real-world effectiveness varies; some implants release inconsistently, leading to gaps in coverage.
Adherence pattern: Highest possible. Once placed, removal requires a procedure. Patients are guaranteed coverage for the implant’s lifespan.
Cost: Highly variable depending on country and clinic. Often £500-2,000 in private UK clinics (when available); much cheaper in some Eastern European clinics; sometimes free in countries where implants are part of state addiction services.
Suits: Patients who have failed both oral and injectable formats due to adherence. Patients in extreme high-risk situations (e.g. those leaving inpatient rehab who cannot trust themselves with daily decisions yet). Patients in jurisdictions where implants are an established part of treatment.
Doesn’t suit: Most patients in markets where implants aren’t standard. The evidence base for implants is weaker than for oral or Vivitrol; quality control varies between products and providers; reversibility requires a surgical removal. We don’t generally recommend pursuing implants unless oral and Vivitrol have both genuinely been tried and failed.
# Direct comparison
For a typical patient choosing between oral and Vivitrol (the two realistic options for most people), the comparison maps roughly:
| Factor | Oral | Vivitrol |
|---|---|---|
| Frequency | Daily | Monthly |
| Cost (US, no insurance) | $4-50/month | $1,500/month |
| Cost (US, with insurance) | $0-15/month | $0-50/month |
| Cost (UK, NHS) | £9.90/item | Not available for alcohol |
| Cost (UK, private) | £10-25/month | Rare |
| Cost (AU, PBS) | Heavily subsidised | Not commonly available |
| Adherence challenge | Significant | Minimal |
| TSM-compatible? | Yes | No |
| Compatible with daily protocol? | Yes | Yes |
| Test-and-discontinue easily? | Yes | Less so |
| Side effects | Mild, transient | Mild, plus injection site |
Most patients start with oral. If oral works and adherence isn’t a problem, there’s no compelling reason to switch. If adherence has been the limiting factor, Vivitrol becomes the natural next step (insurance permitting).
# What about switching between formats
Switching is straightforward in principle. Common patterns:
Oral to Vivitrol: Some prescribers want you to demonstrate tolerance with oral first (typically 7-14 days at 50mg) before the first injection. This catches any rare hypersensitivity reactions before they’re locked in for 30 days. Other prescribers go straight to injection. Either is reasonable.
Vivitrol to oral: Wait for the injection to wear off (about 30 days), then start oral as normal. Some patients pause completely between formats; others bridge with oral starting at week 3-4 of the injection cycle.
Either to TSM: TSM requires oral. If you’ve been on Vivitrol and want to switch to TSM, wait for the injection to wear off, then start the targeted-dose protocol with oral 50mg tablets. The rationale: TSM works through the dose-drink temporal pairing, which constant blockade from Vivitrol doesn’t allow.
# How AlcoLog tracks all of these
AlcoLog’s Medications card has a dedicated naltrexone entry. The dose logging works the same regardless of format. For oral, log each tablet via the 24-hour time picker. For Vivitrol, log the monthly shot date so the system knows when you’re due for the next one (the redose timer can be set in hours + minutes, suitable for monthly intervals). For implants, log the placement date and use the redose timer for the expected expiry.
The last-24h dose list shows what you’ve taken at a glance. Pro-tier location reminders fire when you arrive at a saved location: useful for oral protocols where the cue (arriving at the pub) is the reminder.
AlcoScore deliberately excludes medication use from its scoring. 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.
