Naltrexone: Uses, Dosage, and How It Helps With Alcohol and Opioid Addiction

Naltrexone works differently from the other two common opioid use disorder medications. Instead of activating opioid receptors the way buprenorphine or methadone do, it blocks them. That makes it a genuinely different kind of treatment, with its own dosage rules, its own safety timing, and a second FDA-approved use for alcohol use disorder that neither buprenorphine nor methadone has. This guide covers what naltrexone is, how it’s dosed, and what to expect from treatment in Nashville, using information from SAMHSA, the FDA, and the National Library of Medicine.

What Is Naltrexone and What Is It Used For?

Naltrexone is a medication that blocks the effects of opioids in the brain, rather than activating opioid receptors the way buprenorphine or methadone do. It’s FDA-approved to treat two different conditions, opioid use disorder (OUD) and alcohol use disorder (AUD), and it works somewhat differently for each one, covered in more detail further down this article.

Because naltrexone is an opioid blocker rather than an opioid itself, it doesn’t produce a high, doesn’t cause physical dependence, and has no meaningful potential for misuse. According to SAMHSA, it’s approved as part of a comprehensive treatment plan that also includes counseling, not as a standalone cure.

Naltrexone Generic Name and Classification

Naltrexone is both the generic name and the active ingredient in every version of this medication; there’s no separate brand-only chemical to keep track of. It’s sold under the brand name Vivitrol as a monthly injection, and was formerly sold under the brand names ReVia and Depade as daily tablets. Those two oral brands have been discontinued, but generic naltrexone tablets are still widely available and work the same way.

Unlike buprenorphine (Schedule III) and methadone (Schedule II), naltrexone is not a controlled substance at all. It has no abuse potential of its own, since it blocks opioid effects rather than producing them, so the DEA doesn’t regulate its prescribing the way it does opioid-based medications. In practice, that means any licensed prescriber, not just one with special addiction-medicine registration, can prescribe naltrexone, and it can be picked up at a regular retail pharmacy.

Naltrexone Hydrochloride: What the HCl Form Means

If you’ve seen naltrexone written as “naltrexone hydrochloride” or “naltrexone HCl” on a prescription label or pill bottle, that’s not a different or stronger drug. It’s simply the specific chemical salt form of naltrexone used in tablets. Combining the active drug with hydrochloride makes it more stable and easier for the body to absorb in oral form; the “HCl” designation doesn’t change what the medication does or how it’s dosed.

You’ll see the same naming convention on many other medications (morphine sulfate, buprenorphine hydrochloride, and so on). It’s a pharmaceutical chemistry detail, not a clinical one, so it doesn’t require any special interpretation as a patient.

Naltrexone Dosage: Standard Doses for Opioid and Alcohol Use Disorder

Naltrexone comes in two forms with two different standard doses. The oral tablet is typically taken at 50 mg once daily, with or without food. The extended-release injectable version, sold under the brand name Vivitrol, is given as a 380 mg intramuscular injection into the buttock once every four weeks, administered by a healthcare provider rather than self-administered.

Whichever form is used, and whichever condition is being treated, one requirement stays the same: naltrexone can’t be safely started while opioids are still active in a person’s system. Starting too soon can trigger sudden, severe precipitated withdrawal, so prescribers typically require 7 to 10 days opioid-free (longer for methadone) before the first dose, sometimes confirmed with a urine test.

Naltrexone 50mg Tablet: What It Looks Like and How to Take It

The standard oral tablet contains 50 mg of naltrexone hydrochloride. Appearance varies by manufacturer, since naltrexone is available only as a generic now: tablets are typically round or oval, white or off-white, and marked with a number or manufacturer code rather than one universal imprint, unlike buprenorphine’s “54 411.” If you’re ever unsure what a specific pill is, ask your pharmacist rather than relying on its appearance alone.

Naltrexone tablets are taken by mouth once a day, generally at the same time each day, with or without food (taking it with food can help reduce nausea, the most common side effect). It doesn’t need to dissolve under the tongue or be handled any special way; it’s swallowed like most other oral medications.

25mg vs 50mg Naltrexone: Is a Lower Dose Ever Prescribed?

Yes. A 25 mg dose is sometimes used for the first few days of treatment, before increasing to the standard 50 mg dose, as a way to check for side effects and ease the body into the medication gradually rather than starting at full strength. A common approach is 25 mg daily for the first three days, then 50 mg daily going forward, though your prescriber may adjust this based on how you tolerate it.

You may also come across much lower doses, sometimes 1 to 5 mg, referred to as “low-dose naltrexone” (LDN) in other contexts, such as chronic pain or autoimmune conditions. That’s a different, off-label use with a different mechanism at that dose range, and isn’t part of standard opioid or alcohol use disorder treatment, so it’s worth mentioning only to avoid confusion if you come across the term elsewhere.

Naltrexone Dosage for Alcohol Use Disorder: How It Differs From Opioid Treatment

The standard dose for alcohol use disorder is the same as for opioid use disorder, 50 mg daily by tablet or 380 mg monthly by injection, but the reasoning behind it is different. For opioid use disorder, naltrexone works by physically blocking opioid receptors, so opioids simply don’t produce their usual effect if someone uses them anyway. For alcohol use disorder, naltrexone reduces the rewarding, reinforcing feeling that drinking produces, which tends to lower cravings and heavy drinking days rather than blocking alcohol’s effects outright.

One approach used specifically for alcohol use disorder, sometimes called targeted or as-needed dosing, has some patients take naltrexone an hour or so before a situation where they anticipate drinking, rather than every single day. This isn’t the standard FDA-labeled approach and isn’t right for everyone, so it’s a conversation to have directly with a prescriber rather than something to try independently.

Getting Naltrexone Treatment in Nashville: What to Expect

Because naltrexone isn’t a controlled substance, getting started is often simpler logistically than starting buprenorphine or methadone. It doesn’t require a specially licensed opioid treatment program, and many primary care doctors, psychiatrists, and addiction medicine specialists in the Nashville area are able to prescribe it directly.

What it does require is timing. Your provider will confirm you’ve been opioid-free long enough to start safely (if opioid use disorder is part of the picture) and will talk through whether the daily tablet or the monthly injection makes more sense for your situation. From there, naltrexone is typically combined with counseling or a structured outpatient program rather than used entirely on its own.

If you’re trying to figure out where to start, you can browse licensed treatment providers in our directory, or call the number below and a specialist can help match you with a Nashville-area provider who offers naltrexone.