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Metyrosine (By mouth)

Metyrosine (me-TYE-roe-seen)

Treats symptoms caused by pheochromocytoma (tumor of the adrenal gland). Used before surgery that removes adrenal gland tumors.

Brand Name(s):


There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not take this medicine if you have had an allergic reaction to metyrosine (Demser®).

How to Use This Medicine:


  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
  • Drink extra liquids so you will pass more urine while you are taking this medicine. This will keep crystals from forming in your urine.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are also using phenothiazines, such as prochlorperazine, Compazine®, Mellaril®, Phenergan®, Thorazine®, or Trilafon®, or if you are also using haloperidol (Haldol®).
  • Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol.
  • Avoid drinking alcohol while you are using this medicine.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breast feeding, or if you have heart, kidney, or liver problems.
  • This medicine may make you drowsy. Avoid driving, using machines, or doing anything else that may be dangerous if you are not alert.
  • Make sure any doctor who treats you knows that you are using this medicine. This medicine may affect the results of certain medical tests.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
  • After you have stopped using this medicine, you may have trouble falling asleep at night and have an unusually high energy level. These feelings may last for 2 or 3 days.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing

If you notice these less serious side effects, talk with your doctor:

  • Bleeding or bruising easily.
  • Blood in your urine, or painful urination.
  • Difficulty speaking.
  • Drooling, or dry mouth.
  • Feeling unusually sleepy or tired.
  • Feeling unusually sad, anxious, or confused.
  • Headache.
  • Men: unable to have or keep an erection.
  • Nausea, stomach pain, vomiting, or diarrhea.
  • Seeing or hearing things that are not there.
  • Shaking or twitching of your hands or other body parts.
  • Stuffy nose.
  • Swelling or tenderness in your hands or feet.
  • Swollen breasts, or liquid discharge from your nipples.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 3/19/2020

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