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Naltrexone Side Effects

Medically reviewed by Philip Thornton, DipPharm. Last updated on Jul 5, 2024.

Applies to naltrexone: oral capsule, oral tablet.

Other dosage forms:

Common side effects of naltrexone

Some side effects of naltrexone may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common side effects

  • abdominal or stomach cramping or pain (mild or moderate)
  • anxiety, nervousness, restlessness or trouble sleeping
  • headache
  • joint or muscle pain
  • nausea or vomiting
  • unusual tiredness

Less common side effects

  • chills
  • constipation
  • cough, hoarseness, runny or stuffy nose, sinus problems, sneezing, or sore throat
  • diarrhea
  • dizziness
  • fast or pounding heartbeat
  • increased thirst
  • irritability
  • loss of appetite
  • sexual problems in males

Serious side effects of naltrexone

Along with its needed effects, naltrexone may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking naltrexone:

Less common side effects

  • skin rash

Rare side effects

  • abdominal or stomach pain (severe)
  • blurred vision, aching, burning, or swollen eyes
  • chest pain
  • confusion
  • discomfort while urinating or frequent urination
  • fever
  • hallucinations or seeing, hearing, or feeling things that are not there
  • itching
  • mental depression or other mood or mental changes
  • ringing or buzzing in the ears
  • shortness of breath
  • swelling of the face, feet, or lower legs
  • weight gain

For healthcare professionals

Applies to naltrexone: compounding powder, intramuscular powder for injection extended release, oral capsule, oral tablet.

Nervous system adverse events

Psychiatric

Gastrointestinal

Hepatic

Local

Musculoskeletal

Other

Cardiovascular

Respiratory

Dermatologic

Metabolic

Renal

Hematologic

Ocular

Hypersensitivity

Immunologic

References

1. (2018) "Product Information. Vivitrol (naltrexone)." Alkermes, Inc

2. (2018) "Product Information. Naltrexone Hydrochloride (naltrexone)." Accord Biopharma Inc

Frequently asked questions

Further information

Naltrexone side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.