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Generic name: metyrosine
Brand name: Demser
Dosage form: oral capsule (250 mg)
Drug class: Miscellaneous cardiovascular agents

Medically reviewed by  A Ras MD.

What is metyrosine used for?

Metyrosine is a prescription medicine that is used used to treat pheochromocytoma.


Metyrosine is (–)-α-methyl-L-tyrosine or (α-MPT). It has the following structural formula:


Metyrosine, USP is a white to off-white powder of molecular weight 195.22 g/mol and molecular formula C10H13NO3. It is very slightly soluble in methanol and insoluble in chloroform.

Metyrosine, USP is supplied as capsules for oral administration. Each capsule contains 250 mg metyrosine, USP.

Inactive ingredients are colloidal silicon dioxide, D & C yellow 10, FD & C blue 1, FD & C red 3, FD & C red 40, gelatin, hydroxypropyl cellulose, low-substituted hydroxypropyl cellulose, magnesium stearate, titanium dioxide and water.

Each capsule is imprinted with black pharmaceutical ink which contains: butyl alcohol, dehydrated alcohol, ferrosoferric oxide, isopropyl alcohol, potassium hydroxide, propylene glycol, purified water, shellac and strong ammonia solution.

Meets USP Dissolution Test 2.

Before taking metyrosine, tell your doctor:

  • If you are allergic to metyrosine; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.

This medicine may interact with other drugs or health problems.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take metyrosine with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take metyrosine?

  • Tell all of your health care providers that you take metyrosine. This includes your doctors, nurses, pharmacists, and dentists.
  • Avoid driving and doing other tasks or actions that call for you to be alert until you see how metyrosine affects you.
  • Check your blood pressure as you have been told.
  • Have your urine checked as you have been told by your doctor.
  • Have your blood work checked if you are on metyrosine for a long time. Talk with your doctor.
  • This medicine may affect certain lab tests. Tell all of your health care providers and lab workers that you take metyrosine.
  • In most people who get sleepy when taking metyrosine, changes in sleep pattern happen after stopping metyrosine. People who do not get sleepy when taking metyrosine may also have changes in sleep pattern after stopping metyrosine. Changes like not being able to sleep may last for 2 to 3 days. Talk with your doctor.
  • Talk with your doctor before you drink alcohol or use other drugs and natural products that slow your actions.
  • Tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding. You will need to talk about the benefits and risks to you and the baby.

How is metyrosine best taken?

Use metyrosine as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • Keep taking metyrosine as you have been told by your doctor or other health care provider, even if you feel well.
  • Drink lots of noncaffeine liquids unless told to drink less liquid by your doctor.

What do I do if I miss a dose?

  • Take a missed dose as soon as you think about it.
  • If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
  • Do not take 2 doses at the same time or extra doses.

What are the side effects of metyrosine that I need to call my doctor about immediately?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Feeling confused.
  • Trouble controlling body movements, twitching, change in balance, trouble swallowing or speaking.
  • Drooling.
  • Trouble passing urine.
  • Pain when passing urine.
  • Back pain, belly pain, or blood in the urine. May be signs of a kidney stone.
  • Anxiety.
  • Depression or other mood changes.
  • Hallucinations (seeing or hearing things that are not there).

What are some other side effects of metyrosine?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

If overdose is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out metyrosine?

  • Store at room temperature in a dry place. Do not store in a bathroom.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.




NDC 60219-1621-1
Metyrosine Capsules USP, 250 mg
Rx Only
100 Capsules
Amneal Pharmaceuticals LLC

Imprint AA 05A - metyrosine 250 mg


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