Naltrexone vs Vivitrol: Pill or Monthly Shot?

Side-by-side comparison

One drug, two ways to deliver it

Vivitrol packs naltrexone into tiny polymer beads (microspheres). A provider mixes them with a liquid and injects them deep into the buttock muscle, switching sides each month. It must "ONLY be administered as a deep intramuscular gluteal injection."² The beads wear down slowly. Drug levels peak about 2 hours after the shot and again 2 to 3 days later, start a slow fall around day 14, and stay measurable for more than a month.² Over 28 days, one shot delivers 3 to 4 times the total naltrexone of a 50 mg pill every day.² Pellets placed under the skin are a third form, but no naltrexone implant is FDA-approved in the US.

You don't have to try pills first; pretreatment with oral naltrexone is not required.²

Is there a generic Vivitrol?

Two products come up, and neither is easy to find.

• Teva's generic. The FDA approved it (ANDA 213195) on July 6, 2023. The FDA's database now lists it as discontinued.⁹
• Amneal's unbranded version. It is made by Alkermes and sold under Vivitrol's own FDA application (NDA 021897), so it is not a generic.¹⁰ Its listed marketing start date is May 1, 2026.¹¹ In a July 2026 SEC filing, Alkermes said Amneal "did not wish to order any Batches under the Agreement."¹²

We found no price for either.

Generic tablets are widely available. Seven makers hold FDA approvals for generic naltrexone tablets, all marketed as prescription drugs. ReVia, the original brand, is listed as discontinued.⁹ The status of every naltrexone brand, including ReVia and Depade, is on naltrexone brand names.

Neither form has been shown to cut drinking more

The VA and Department of Defense guideline says "the two formulations have not been directly compared to evaluate whether the long-acting injectable formulation improves clinical outcomes." It rates naltrexone in either form "Strong for" alcohol use disorder.³

Against placebo, the pill has the stronger record.

In Vivitrol's main approval trial, 624 alcohol-dependent adults, most of them drinking up to the start, got at least one shot. Over 6 months, the 380 mg dose cut the rate of heavy drinking days by 25% compared with placebo.¹⁶ In the label's breakdown of that trial, the clear benefit came from the 53 people (8%) who had stopped drinking for the week before the first shot. "The same treatment effects were not evident" in the 92% who were still drinking at the start.² That is why the approved use asks you to stop first.

The shot keeps more people on treatment

A 2025 systematic review found 15 studies that compared the two forms directly (3 small open-label randomized trials and 12 studies of past records) and pooled the 7 that reported comparable outcomes. People on the shot were more likely to still be on treatment at 3 months (odds ratio 1.43) and at 6 months (odds ratio 1.96). Hospital stays and emergency visits did not differ.⁴

The two randomized trials in alcohol use disorder found no significant difference between the forms⁴:

• Primary care, 237 people: 29% on the shot and 23% on pills either stopped drinking or drank moderately.
• Hospitalized veterans, 54 people (pilot): adherence was 61% on the shot and 62% on pills.

In opioid use disorder the gap was wider. In a 60-person trial after inpatient withdrawal, 57.1% on the shot were still in treatment at 6 months, against 28.1% on pills.¹⁷

Most of the pooled data come from records, not trials. Pill adherence was judged from pharmacy refills, which likely overstates it, and people picked for the shot may have had more severe drinking problems.⁴ Adherence is low on both. In one VA study, people had their medicine on hand for 49.8% of days on pills and 54.6% on the shot over 6 months.¹⁸

The VA/DoD advice: injectable naltrexone "should be considered when medication adherence is a significant concern and the patient is agreeable to receive monthly injections by a provider."³

Before the first dose: opioids and alcohol

Opioids. Both forms block opioids, so starting either one with opioids still in your body can bring on sudden withdrawal. Both labels advise at least 7 to 10 days opioid-free, and warn that people coming off buprenorphine or methadone can be at risk of withdrawal for as long as 2 weeks.^1,2 This withdrawal "can be severe enough to require hospitalization," and it has happened in people treated for alcohol whose prescriber didn't know about their opioid use.² Tell your prescriber about every opioid you've taken, including tramadol and any medicine that contains an opioid.¹ How the shot compares with Suboxone for opioid use disorder is on naltrexone vs Suboxone.

Alcohol. The tablet label sets no drinking rule before you start.¹ Vivitrol does: "Patients should not be actively drinking at the time of initial VIVITROL administration."²

Neither treats alcohol withdrawal. Vivitrol "does not eliminate nor diminish alcohol withdrawal symptoms."² If you're physically dependent on alcohol, plan withdrawal care with a clinician first.

Injection-site reactions are the shot's own risk

The two labels report side effects from different kinds of studies, so read the columns separately, not against each other.

Sources: tablet label, adverse reactions; Vivitrol label, Table 1.^1,2

Pooled trials show nausea (risk ratio 1.73) and vomiting (1.53) more often on naltrexone than on placebo.¹⁴ After a Vivitrol shot, nausea is usually mild, fades within a few days, and is less likely with later shots.²

Most injection-site reactions in trials were tenderness, hardening, pain, lumps or itching. After approval, reports came in of reactions "including induration, cellulitis, hematoma, abscess, sterile abscess, and necrosis." "Some cases required surgical intervention, including debridement of necrotic tissue," some left significant scars, and most were in women.² Because it's a deep muscle shot, people with low platelets or a bleeding disorder need extra caution.²

Few people stopped because of side effects. In two 12-week tablet trials, 5 of 93 people stopped because of nausea.¹ In Vivitrol's pooled alcohol trials, 9% stopped for a side effect (most often an injection-site reaction), against 7% on placebo.²

Vivitrol also carries warnings about allergic reactions, including anaphylaxis, and two cases of a lung condition called eosinophilic pneumonia, both needing a hospital stay.²

The liver warning is the same on both labels

Both labels state: "Cases of hepatitis and clinically significant liver dysfunction were observed" with the drug, in clinical trials and after approval. Both say to stop it if signs of acute hepatitis appear. Neither has a boxed warning.^1,2

• When liver enzymes were high, other causes were often found, such as alcohol-related liver disease, hepatitis B or C, or other drugs.^1,2
• Clear liver injury was tied to high doses. In studies of up to 300 mg a day, naltrexone "causes hepatocellular injury in a substantial proportion of patients exposed at higher doses."¹
• In alcohol trials, a rise in the liver enzyme AST was as common on Vivitrol as on oral naltrexone (1.5% each), against 0.9% on placebo.²
• Vivitrol needs no dose change for mild to moderate liver impairment. Neither form has been properly studied in severe liver disease.^1,2

With the shot, safety rules last a month

The rules are the same for both forms. The shot stretches the timeline from a day to about 4 weeks.^1,2

• Opioid overdose. Tolerance drops after detox. Once the block fades, a smaller opioid dose than you used before can be fatal, and fatal overdoses have been reported near the end of a Vivitrol dosing interval or after a missed shot. Both labels advise having an overdose-reversal drug such as naloxone available.^1,2
• Pain care and emergencies. Carry a card or other ID saying you take naltrexone. Pain can be treated with regional numbing and non-opioid pain relievers.^1,2 With the shot, tell any surgeon or dentist ahead of time, because the block can last weeks.²
• Mood. In Vivitrol's alcohol trials, suicidal thoughts and attempts were more common on the drug than on placebo (1% vs 0%), and low mood was reported by 10% vs 5% in the main trial.² For tablets, depression and suicidal thoughts have been reported after approval in people treated for opioid dependence, with no causal link shown.¹

Cost: pills vs the shot

The Drugs.com figure is a cash price, and NADAC and the Medicare limit are reference costs, not your price.^5,19

Insurance. In 2023, 49 of 53 Medicaid fee-for-service programs covered the tablets and 46 covered the shot.⁶ In 241 Medicaid managed care plans in 2021, 84.2% covered the tablets and 72.6% the shot, and 42.8% of the plans covering the shot required prior authorization or quantity limits.⁷ If you want the shot, ask about prior authorization early.

Co-pay help. Alkermes's Vivitrol program takes up to $500 off each prescription, up to $6,000 a year, for people with commercial insurance or none. It is "not valid for patients enrolled in Medicare, Medicaid, or other federal or state healthcare programs," and it covers the drug, not the fee for giving the shot.^21,22 Shot-by-shot math and the full co-pay terms are in the Vivitrol section of naltrexone cost.

Only 2 of the 13 programs we compare offer the shot

Tablets can be prescribed online and filled at a pharmacy.¹ The shot needs a provider in the room.² Of the 13 US online programs we compare (checked October 17, 2026), two say they offer Vivitrol:

• Boulder Care lists Vivitrol among its alcohol medicines.²³
• Rezolv Health (California, Washington, Nevada) says Vivitrol "requires a monthly in-person or in-office injection. Your provider will coordinate this."²⁴

Workit Health says "our providers prescribe naltrexone but not Vivitrol."²⁵ Talkspace says its providers "do not prescribe or administer injectable medications," and Oar Health says injections aren't available for home delivery.^26,27

Which one fits you

There's no formal rule. These are the trade-offs the labels and guidelines point to.

Either form is meant to be one part of a wider plan that includes counseling or other support.^1,2 For more on targeted dosing, see the Sinclair Method. For first-hand accounts of the shot, see Vivitrol stories.

Seven quick facts from the labels

1. Prescription only. Every marketed naltrexone tablet is listed by the FDA as a prescription drug.^1,9
2. Into a muscle, not a vein. Vivitrol goes deep into the buttock muscle, never into a vein.²
3. Neither form eases withdrawal. Vivitrol doesn't ease alcohol withdrawal, and either form can trigger opioid withdrawal in someone with opioids still in their body.^1,2
4. The 7-to-10-day wait is about opioids. The tablets set no drinking rule; Vivitrol asks that you not be actively drinking at the first shot.^1,2
5. Opioid tolerance drops. Tolerance falls after detox, which is why overdose risk rises when the block wears off.¹
6. No boxed warning now. Neither current label has a boxed warning; both still warn about the liver.^1,2
7. No cheap generic Vivitrol. The only FDA-approved generic we found is listed as discontinued, and the Amneal version is an unbranded Vivitrol made by Alkermes.^9,10

Naltrexone is not a controlled substance in either form. Federal regulations name it as an exception in the opiate schedule (21 CFR §1308.12).⁸ See is naltrexone a controlled substance?