Metyrosine Side Effects

Medically reviewed by Drugs.com. Last updated on Feb 4, 2025.

Applies to metyrosine: oral capsule.

Serious side effects of metyrosine

Along with its needed effects, metyrosine 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 as soon as possible if any of the following side effects occur while taking metyrosine:

More common side effects

• diarrhea
• drooling
• trembling and shaking of hands and fingers
• trouble in speaking

Less common side effects

• anxiety
• confusion
• hallucinations (seeing, hearing, or feeling things that are not there)
• mental depression

Rare side effects

• black, tarry stools
• blood in urine or stools
• unusual bleeding or bruising
• muscle spasms, especially of neck and back
• painful urination
• pinpoint red spots on skin
• restlessness
• shortness of breath
• shuffling walk
• skin rash and itching
• swelling of feet or lower legs
• tic-like (jerky) movements of head, face, mouth, and neck
• unusual tiredness or weakness

Other side effects of metyrosine

Some side effects of metyrosine 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

• drowsiness
• diarrhea

Less common side effects

• decreased sexual ability in men
• dryness of mouth
• nausea, vomiting, or stomach pain
• stuffy nose
• swelling of breasts or unusual milk production

After you stop using this medicine, it may still produce some side effects that need attention. During this period of time, Check with your doctor immediately if you notice the following side effects:

Also, after you Stop taking metyrosine, you may have feelings of increased energy or you may have trouble sleeping. However, these effects should last only for two or three days.

Further information

Metyrosine 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.

Medical Disclaimer