Vivitrol (Naltrexone) at a glance: schedule, half-life, and class
- Generic name
- Naltrexone hydrochloride
- Brand names
- Vivitrol (extended-release injection); Revia (tablets, discontinued brand)
- Drug class
- Opioid antagonist
- US legal status
- Prescription only; not a controlled substance
- Approved uses
- Alcohol dependence; prevention of relapse to opioid dependence after detox
- Forms
- 50 mg tablets; 380 mg monthly injection
- Onset
- About 1 hour (tablets)
- Half-life
- About 4 hours; 6-beta-naltrexol about 13 hours
- Combined with
- Bupropion in Contrave for weight management
Vivitrol uses: what naltrexone is prescribed for
Naltrexone reduces heavy drinking and cravings in alcohol use disorder, and blocks the effects of opioids to help prevent relapse after someone has fully withdrawn from opioids.[1]
Unlike buprenorphine and methadone, naltrexone does not activate opioid receptors. People must be opioid-free for 7 to 10 days before starting, or 7 to 14 days after long-acting opioids, to avoid sudden withdrawal.[1]
Vivitrol dosage: how naltrexone is usually prescribed
The figures below come from the FDA-approved label and describe how prescribers typically use naltrexone. They are not personal dosing advice. A prescriber sets the dose for each person and adjusts it over time.[1]
| Product | Typical adult dose | Notes from the label |
|---|---|---|
| Tablets | 50 mg once a day | Some programs use 100 mg every other day or 150 mg every third day |
| Vivitrol injection | 380 mg into the buttock muscle every 4 weeks | Given by a clinician; alternate sides |
| Before starting (opioid use disorder) | 7 to 10 days without short-acting opioids | A naloxone challenge test may be used to confirm |
Vivitrol (naltrexone) side effects and risks
Common side effects include nausea, headache, dizziness, tiredness, and trouble sleeping. Injection-site reactions, sometimes severe, can occur with Vivitrol.[1]
Overdose after stopping: naltrexone lowers opioid tolerance. Taking opioids after a missed dose, after the injection wears off, or in an attempt to override the blockade can cause a fatal overdose.[1]
Liver: liver injury has been reported at high doses. An earlier boxed warning about liver toxicity was removed in 2013, but liver tests are checked in people with liver disease.[1]
Vivitrol interactions: what not to mix with naltrexone
Choose what it would be combined with:
| Combined with | What happens | Label guidance |
|---|---|---|
| Opioid pain medicines, cough and diarrhea medicines with opioids | Blocked effect; little or no relief | Plan pain care in advance; carry a wallet card |
| Opioids taken to override the block | Overdose and death | Dangerous |
| Methadone or buprenorphine | Sudden, severe withdrawal | Do not combine |
| Alcohol | No dangerous interaction; may reduce the urge to drink | Can be started while still drinking |
This is not a full list. A pharmacist can check a complete medication list, including supplements and over-the-counter products.[1]
Can you overdose on naltrexone?
Naltrexone itself has a wide safety margin. The danger is opioid overdose: in people whose tolerance has dropped, or who take large amounts of opioids to overcome the blockade.[1]
If someone may have overdosed
- Call 911 if the person is unresponsive, cannot be woken, has blue or gray lips, or is breathing slowly or not at all.
- Give naloxone (Narcan or a generic nasal spray, sold without a prescription) into one nostril. If there is no response after 2 to 3 minutes, give another dose.
- If you are trained, give rescue breaths. Otherwise place the person on their side so they do not choke.
- Stay with them. Naloxone can wear off before naltrexone does, so the overdose can return even after the person wakes up.
- Most states have Good Samaritan laws that protect people who call 911 for an overdose from some drug charges.
Does naltrexone cause withdrawal?
Naltrexone does not cause physical dependence, and stopping it does not cause withdrawal. Starting it while opioids are still in the body causes sudden opioid withdrawal, which is why people must be opioid-free first.[1]
- Minutes to hoursPrecipitated withdrawalIf taken too soon after opioids: vomiting, diarrhea, sweating, agitation, and body aches.
- Day 1 to 2PeakSymptoms can be intense after an injection, which cannot be removed, and may need hospital care.
- After stoppingNo withdrawalOpioid tolerance stays low, so any return to opioid use carries a high risk of overdose.
Warning: After stopping naltrexone, a person's tolerance to opioids is low. Using a previous dose of opioids can cause a fatal overdose. Keep naloxone at hand.
How to get prescribed Vivitrol (naltrexone) legally in the US
In the United States, naltrexone is a prescription medicine but not a controlled substance. Any licensed prescriber can prescribe it, including in primary care and by telemedicine, without a DEA registration.
- Refills: refills follow ordinary prescription rules.
- Pharmacies: a legitimate pharmacy always requires a valid prescription, has a licensed pharmacist available, and is licensed in the state it ships to. The FDA's BeSafeRx tool and the NABP's safe pharmacy list help confirm a pharmacy is real.[2][3]
- Cost: generic tablets are inexpensive. Vivitrol costs over $1,500 per injection without insurance but is covered by Medicaid and most insurers, often with prior authorization.
Traveling: keep the medicine in its original pharmacy container and carry a copy of the prescription. Check the rules of the destination country before travel, because many countries restrict controlled medicines or require a permit.
Can you order Vivitrol (naltrexone) online legally?
Yes, but only with a valid prescription and only from a pharmacy licensed in your state. Many licensed pharmacies, including mail-order pharmacies run by insurers, fill naltrexone prescriptions online and ship them. Buying naltrexone from a website that does not require a prescription is illegal, and the product is often fake.[2][4]
- See a licensed clinicianA clinician evaluates you in person or by telemedicine and decides whether naltrexone is appropriate.
- The prescription goes to a pharmacyPrescriptions are usually sent electronically, straight from the prescriber to the pharmacy you choose.
- The pharmacy checks and fills itA pharmacist verifies the prescription and your identity, then dispenses the medicine in person or by mail.
Signs that an online seller is illegal:
- It sells naltrexone with no prescription, or after only a short online questionnaire.
- It takes orders through social media, messaging apps, or email.
- It asks for payment in cryptocurrency, gift cards, or money transfers.
- It has no US street address, no state pharmacy license, and no pharmacist to speak to.
- Its prices are far below those of ordinary pharmacies, or it ships from another country.
The FDA's BeSafeRx tool links to each state's license lookup, and the National Association of Boards of Pharmacy lists verified online pharmacies.[2][3]
Vivitrol price: how much does Vivitrol (naltrexone) cost without insurance?
Generic tablets are inexpensive. Vivitrol costs over $1,500 per injection without insurance but is covered by Medicaid and most insurers, often with prior authorization.
What you pay depends on the strength, the number of doses, your insurance plan, and the pharmacy. Cash prices for the same prescription can differ several times over between pharmacies in the same town, so check current prices before you fill it.
Ways to pay less, legally:
- Ask the prescriber whether a generic naltrexone is available. FDA-approved generics work the same way as the brand and usually cost much less.
- Compare cash prices between pharmacies before you fill the prescription.
- Use a free prescription discount card, such as GoodRx or SingleCare, when you pay cash. These cards cannot be combined with insurance on the same fill.
- For brand-name medicines, check the manufacturer's savings program or patient assistance program.
- Ask about a 90-day supply or your insurer's mail-order pharmacy, which often lowers the cost per dose when your prescriber agrees it is appropriate.
Warning: A price far below what licensed pharmacies charge, especially with no prescription required, is a strong sign of an illegal seller and counterfeit medicine.[2]
Is Vivitrol legal? Naltrexone legal status in other countries
| Country | Status |
|---|---|
| United Kingdom | Prescription-only medicine |
| Canada | Prescription only |
| Australia | Schedule 4 prescription medicine |
| International | Not under UN control |
Laws change and differ in detail. Check current rules before carrying any controlled medicine across a border.[5]
Common questions about Vivitrol (naltrexone)
Is Vivitrol (naltrexone) addictive?
No. It has no opioid effects, does not cause a high, and does not cause withdrawal when stopped.
Can you drink alcohol on Vivitrol (naltrexone)?
It is safe to drink, and some programs start it while people are still drinking, but it is meant to help reduce drinking.
What is low-dose Vivitrol (naltrexone) (LDN)?
Doses of about 1 to 4.5 mg, usually compounded, are used off-label for chronic pain and autoimmune conditions. Evidence is limited and the FDA has not approved these uses.
How is Vivitrol (naltrexone) different from naloxone?
Both block opioid receptors. Naloxone works fast and briefly to reverse overdose; naltrexone lasts a day to a month to prevent relapse.
Can Vivitrol (naltrexone) help with weight loss?
Combined with bupropion in Contrave, it is approved for weight management.
Can you buy Vivitrol (naltrexone) without a prescription?
No. Vivitrol (naltrexone) is a prescription-only medicine in the US, and a pharmacy may dispense it only with a valid prescription. The FDA warns that websites selling prescription medicines without one are often illegal and that their products can be counterfeit, contaminated, or the wrong strength. The legal route is a visit with a licensed clinician, in person or by telehealth, and a prescription filled at a state-licensed pharmacy. The FDA's BeSafeRx tool and the NABP's safe pharmacy list help confirm an online pharmacy is real.
Sources
- Vivitrol (naltrexone) prescription information. DailyMed, US National Library of Medicine.
- BeSafeRx: Your Source for Online Pharmacy Information. US Food and Drug Administration.
- Safe Pharmacy. National Association of Boards of Pharmacy.
- One Pill Can Kill. US Drug Enforcement Administration.
- International drug control conventions. United Nations Office on Drugs and Crime.
