Patient handout

Naltrexone (Vivitrol, Revia)

You have been prescribed naltrexone. This page explains what it is, what to expect, and when to call.

Prepared by Alice Tran, PMHNP-BC, FNP-BC · Alice Tran Psychiatric Care · Updated October 2026

What it is

Naltrexone blocks opioid receptors. For alcohol use disorder it reduces craving and the reward from drinking, which helps people drink less or stay abstinent. For opioid use disorder it blocks the effect of opioids after detox. It is not addictive and does not cause a high. It comes as a daily tablet or a monthly injection (Vivitrol).

How to take it

• Tablet: take it once a day, with food to reduce nausea. Injection: given in the clinic every four weeks.
• If you miss a dose, take it when you remember unless the next dose is close. Do not double up.
• You do not need to stop drinking completely before starting the tablet for alcohol use, but you must be opioid-free for 7 to 14 days before any form of naltrexone.

What to expect, and when

• Cravings and the pull toward a second drink usually ease within the first week or two.
• Nausea, headache, and tiredness in the first days usually fade.
• We check liver function before starting and periodically after.
• It works best alongside counseling or a support program.

Common side effects

Nausea, headache, dizziness, tiredness, trouble sleeping, anxiety, and, with the injection, soreness at the injection site.

Call the office the same day if

Stopping

Naltrexone can be stopped without a taper. Tell us before stopping so the plan can be adjusted. Keep in mind that after stopping, opioid tolerance is low and a previously tolerated opioid dose can be fatal.

Good to know

• Opioid warning: naltrexone blocks opioid pain medicines. Taking large doses of opioids to overcome the block can cause overdose and death. Carry a card or wear a bracelet saying you take naltrexone, and tell every clinician, dentist, and emergency team.
• Tell us before any surgery or procedure that may need opioid pain control.
• It does not treat alcohol withdrawal. If you drink heavily every day, tell us before cutting back, since withdrawal needs its own plan.
• Tell us if you are pregnant, planning pregnancy, or breastfeeding.

This handout is general education, not medical advice, and reading it does not create a clinician-patient relationship. It may be incomplete or out of date and is provided as is, without warranty. Do not start, stop, or change any treatment based on this page alone; follow the instructions from your own clinician and the dose on your prescription label, and call the office if anything here differs from what you were told. To the fullest extent permitted by law, Alice Tran Psychiatric Care, Alice Tran Nurse Practitioner LLC, and its authors disclaim all liability arising from its use. In an emergency, call 911. If you are in crisis, call or text 988.

Related: All patient resources