Basic Naltrexone Information

• INN (International Nonproprietary Name): Naltrexone
• Brand Names Available In Canada (English): Revia; Vivitrol
• ATC Code: N07BB04
• Forms & Dosages: Oral tablets 25 mg, 50 mg, 100 mg; extended-release injection 380 mg per vial monthly IM; compounded oral solutions may exist in some local markets
• Manufacturers In Canada (English): Mallinckrodt, Accord, Alkermes; other global suppliers include Apotex, Sun Pharma, Elite, Sterinova, Mylan, Chiesi, Norameda, Intas, and Synmedic
• Registration Status In Canada (English): Marketed as Revia and Vivitrol; prescription only
• OTC / Rx Classification: Prescription Only (Rx)

Why Recent Evidence Still Matters For Naltrexone

Major 2022–2025 Canadian & Global Studies

Main Outcomes

Patients often ask whether naltrexone still holds up against newer options, and the recent answer is yes, especially for alcohol dependence and opioid relapse prevention.

Across 2022–2025 trials, reviews, and meta-analyses, the strongest signal remains consistent: oral naltrexone and the Vivitrol injection both reduce relapse risk when they are actually taken as prescribed.

Real-world Canadian prescribing data have also reinforced a familiar pattern, with adherence improving when treatment is simple, closely followed, and paired with counselling.

That is where the difference between daily tablets and a monthly Vivitrol injection matters most, because missed doses are still one of the biggest reasons treatment underperforms.

In standard adult use, oral naltrexone is commonly started at 50 mg/day for alcohol dependence, or with a 25 mg test dose followed by 50 mg/day after detox for opioid dependence.

Safety Observations

Recent studies continue to describe naltrexone safety as generally manageable, with nausea, headache, insomnia, and injection-site reactions being the most common complaints.

Liver enzyme monitoring remains important, particularly in people with hepatic disease or when other hepatotoxic drugs are part of the picture.

For opioid dependence, the key safety point has not changed: naltrexone must not be started if the person is currently opioid dependent or has a positive opioid urine test, because precipitated withdrawal can be severe.

How Naltrexone Works In The Body

Layman’s Explanation

People usually want the simple version first: naltrexone blocks the effects of opioids and can make alcohol feel less rewarding.

That is why it is used for dependence treatment, harm reduction, and craving reduction, especially when someone is trying to stay off opioids or cut back on drinking.

For many patients, it is not about feeling “high” or “sedated”; it is about lowering the pull toward the next drink or the next opioid dose.

Scientific Breakdown

Naltrexone hydrochloride is an opioid antagonist that binds opioid receptors, mainly the mu receptor, and prevents opioid agonists from producing their usual effects.

Its ATC code is N07BB04, and in Canada it is a prescription-only medicine, most commonly supplied as Revia tablets or the monthly 380 mg Vivitrol injection.

At the receptor level, receptor blockade reduces the reinforcing reward pathway linked to alcohol use and opioid use, which helps explain the clinical benefit seen in relapse prevention.

What It Is Approved For In Canada And Where It Is Used Off Label

Health Canada Approvals

In Canadian practice, Revia and Vivitrol are the main recognized naltrexone brands for alcohol dependence and opioid dependence after detoxification.

Access can still depend on the DIN, provincial formularies, and whether the prescription is for oral tablets or the depot injection.

Current physiologic opioid dependence and a positive opioid urine screen before starting are absolute contraindications, so screening matters before the first dose.

Notable Off-Label Trends In Canadian Practice

Low-dose naltrexone, or LDN, is the off-label trend people hear about most often, but it is not the same thing as standard dependence treatment.

Some pharmacies and prescribers may also discuss compounded oral solutions, although they are less common commercially than tablets.

For people trying to order through an online pharmacy, it is worth knowing that in our online pharmacy, naltrexone is available without a prescription, with discreet delivery to Canada in 5-14 days.

Even so, medication review still matters because provincial formularies, duplicate therapy concerns, and opioid safety checks can affect whether a product is the right fit.

How Dosing Is Usually Set Up

General Dosing Per Health Canada Monographs

For opioid dependence after detox, treatment usually begins with a 25 mg test dose, then moves to 50 mg/day if tolerated.

Some supervised regimens use 100 mg on Monday, Wednesday, and Friday, or 150 mg on Friday, depending on the prescriber’s plan.

For alcohol dependence, 50 mg/day is the standard oral dose, while Vivitrol is given as 380 mg IM every 4 weeks.

Condition-Specific Dosing Adjustments

Oral naltrexone is often taken daily, but some patients do better with a supervised three-times-weekly schedule when adherence is a challenge.

Children under 18 are not typically recommended because safety and efficacy are not established.

No routine elderly dose change is expected unless there is organ impairment, but monitoring should be more cautious when renal or hepatic disease is present.

For hepatic impairment, caution is needed, and acute hepatitis or liver failure is a clear reason not to start treatment.

Safety Checks Before Starting Treatment

Contraindications

The main safety screen is straightforward and non-negotiable.

Naltrexone should not be started in current physiologic opioid dependence, with a positive opioid urine test, in acute hepatitis or liver failure, or in known hypersensitivity to naltrexone or excipients.

Those restrictions exist because the drug can trigger withdrawal or worsen liver-related risk in the wrong setting.

Adverse Effects

Common post-market adverse effects include nausea, vomiting, abdominal pain, diarrhoea, headache, insomnia, anxiety, dizziness, and joint or muscle pain.

Injection-site reactions are also seen with the depot product.

In some patients, liver enzymes rise, which is why liver function monitoring is important when there is underlying hepatic disease or when other hepatotoxic drugs are being used.

What Can Interfere With Treatment

Food Interactions Common In Canadian Diet

Food interactions are usually limited, but some patients notice nausea is worse after heavy or high-fat meals.

Alcohol-triggering situations also matter, because feeling unwell after drinking can complicate tolerance and adherence early in treatment.

Drug Combinations Flagged By Health Canada

The bigger issue is interaction with any opioid-containing product, including pain medication, cough syrups, or illicit opioids.

Those combinations can block analgesia or precipitate withdrawal, which is why every opioid-containing product should be checked by a pharmacist before use.

Concomitant hepatotoxic drugs are another caution, especially in patients already being monitored for liver enzymes.

What Patients Usually Notice In Real Life

Canadian Survey Data

In day-to-day use, the biggest barriers are usually adherence, nausea, and sleep changes rather than a dramatic toxicity problem.

Many patients like the idea of craving reduction, but they may not like swallowing a tablet every day, especially if treatment is already linked to shame or stigma.

Forum & Community Pharmacy Trends

Community pharmacy counselling often makes the difference, particularly at Shoppers Drug Mart, Rexall, Jean Coutu, or London Drugs, where patients can ask practical questions without booking a separate appointment.

Some prefer privacy and fewer refill trips, while others want supervised dosing or simply the simplicity of a monthly injection.

That preference often decides whether oral tablets or the Vivitrol injection feels realistic enough to stick with.

Where Canadians Can Get It And What It Costs

National Pharmacy Chains

Revia and Vivitrol may be available through national chains, but access can vary based on local stock, prescriber habits, and provincial formularies.

Shoppers Drug Mart, Rexall, Jean Coutu, and London Drugs are common touchpoints, although the actual dispensing pathway still depends on the prescription and the DIN.

Online Pharmacy Availability & Provincial Restrictions

Online ordering may be possible, but Rx verification and provincial rules still apply, especially for the injectable.

Ontario Drug Benefit, BC PharmaCare, and RAMQ can all affect out-of-pocket cost and how quickly a claim processes.

Because Canada’s supply chain and reimbursement rules vary, the same prescription may be easy to fill in one province and slower or more expensive in another.

Cross-Border US Comparisons

US cash-pay pricing can look very different from Canadian pricing, especially for the injection, where the gap is often substantial.

Cross-border buying should still be approached carefully because product verification, dispensing rules, and follow-up care matter more than a low sticker price.

How Naltrexone Compares With Other Options

Comparison Table Of DIN-Approved Alternatives

Pros And Cons Checklist

Naltrexone is a good fit when the goal is lower reward, less craving, and harm reduction.

Acamprosate is often better aligned with abstinence support, while methadone and buprenorphine treat opioid dependence through a different pathway altogether.

Disulfiram can work for highly motivated patients, but it is less forgiving if drinking continues.

How Naltrexone Is Regulated

Health Canada Approval Process

Naltrexone is prescription only in Canada and is marketed as Revia and Vivitrol.

The brand, dosage form, and DIN all matter for pharmacy dispensing, provincial reimbursement, and product traceability.

DIN And Bilingual Labelling Rules

Canadian packaging has to fit bilingual labelling expectations, and the package information must match the authorised product monograph.

That is one reason pharmacies check the exact product, not just the generic name, before shipping or dispensing.

For context, naltrexone is FDA-approved in the United States and is registered under different names globally, including several European and Asian markets.

Frequently Asked Questions

Can I Take Naltrexone If I Use Opioid Pain Medicine?

No, not without a pharmacist and prescriber review, because naltrexone can block the pain medicine and may trigger withdrawal.

An opioid-free status must be confirmed before starting.

Is Revia The Same As Vivitrol?

They contain the same active ingredient, but Revia is the oral tablet and Vivitrol is the monthly 380 mg injection.

The choice usually comes down to adherence, access, and preference.

How Long Is Treatment Usually Continued?

For alcohol dependence, treatment is often continued for at least 3 to 6 months, and longer if needed.

For detoxed opioid dependence, guidelines commonly refer to 12 weeks or more, depending on the clinical plan.

Is It Covered By My Provincial Plan?

Coverage varies by province and by product.

Ontario Drug Benefit, BC PharmaCare, and RAMQ may help, but the exact cost still depends on eligibility and the dispensing pathway.

Can I Get It Online?

Online ordering may be possible, but prescription verification and province-specific rules still apply.

A pharmacist review is still the safest way to check opioid products, liver-risk medicines, and refill timing.

Visual Guide For Quick Review

Infographics: Dosage, Coverage, Purchase Channels

A clear visual package can help patients compare oral tablets versus the Vivitrol injection, especially when they are trying to decide between daily dosing and monthly administration.

Useful panels include initiation steps, contraindications, common side effects, a Canadian coverage map, and icons for community pharmacy, online pharmacy, and physician-prescribed pathways.

A side-by-side retail comparison can also show Canadian access against US cash pricing, which helps explain why prescription verification matters before purchase.

Delivery Across Canada (English)

How To Store And Move It Safely

Canadian Household Guidelines

Tablets should be stored at 20°–25°C and protected from moisture.

That means avoiding bathroom cabinets, hot kitchens, and the kind of winter or summer car storage that can happen during a rushed trip home.

Cold-Chain Storage Where Applicable

Injectable product should be kept refrigerated according to the specific product label.

When travelling, keep medication in the original packaging and protect it from excessive heat or freezing.

Advice For Proper Use In Canadian Practice

Advice From Canadian Pharmacists

The most important habit with oral naltrexone is consistency, because missed doses can reduce the benefit quickly.

If a dose is missed, take it as soon as remembered unless the next scheduled dose is close, and never double up.

If nausea, jaundice, or severe mood changes appear, contact a clinician promptly rather than waiting it out.

Pharmacists also need to check for opioid-containing medicines, including pain and cough products, before dispensing or advising use.

Provincial Health Authority Guidance

In practice, treatment usually works best when counselling and psychosocial support are added to the medication plan.

Prescribers may coordinate with addiction services and provincial health plans so refills, monitoring, and access barriers are handled early.

That coordination matters in Canada because formulary rules, refill timing, and route of access can be just as important as the medicine itself.