In the U.S.—

• Antihypertensive, pheochromocytoma

Metyrosine (me-TYE-roe-seen) belongs to the general class of medicines called antihypertensives. It is used to treat high blood pressure (hypertension) caused by a disease called pheochromocytoma (a noncancerous tumor of the adrenal gland).

Metyrosine reduces the amount of certain chemicals in the body. When these chemicals are present in large amounts, they cause high blood pressure.

Metyrosine is available only with your doctor's prescription, in the following dosage form:

Oral
• Capsules (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For metyrosine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to metyrosine. Also tell your health care professional if you are allergic to any other substances, such as foods, sulfites or other preservatives, or dyes.

Pregnancy—Studies on effects in pregnancy have not been done in either humans or animals.

Breast-feeding—It is not known whether metyrosine passes into breast milk. However, this medicine has not been reported to cause problems in nursing babies.

Children—Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of metyrosine in children with use in other age groups.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of metyrosine in the elderly with use in other age groups.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

• Kidney disease or
• Liver disease—Effects of metyrosine may be increased because of slower removal from the body

• Mental depression (or history of) or
• Parkinson's disease—Metyrosine may make these conditions worse

Take this medicine only as directed by your doctor. Do not take more or less of it than your doctor ordered.

To help you remember to take your medicine, try to get into the habit of taking it at the same times each day.

Dosing—

The dose of metyrosine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of metyrosine. If your dose is different, do not change it unless your doctor tells you to do so:

• For oral dosage forms (capsules):
  • Adults and children 12 years of age and older: 1000 milligrams to 3000 milligrams (1 to 3 grams) a day, divided into four doses.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

While taking this medicine, it is important that you drink plenty of fluids and urinate often. This will help prevent kidney problems and keep your kidneys working well. If you have any questions about how much you should drink, check with your doctor.

This medicine will add to the effects of alcohol and other CNS depressants (medicines that slow down the nervous system, possibly causing drowsiness). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; tricyclic antidepressants (medicine for depression); muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are taking this medicine.

Before having any kind of surgery (including dental surgery), tell the medical doctor or dentist in charge that you are taking this medicine.

This medicine may cause most people to become drowsy or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert.

Along with its needed effects, a medicine 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:

• More common
  • Diarrhea;  drooling;  trembling and shaking of hands and fingers;  trouble in speaking 
  
  

• Less common
  • Anxiety;  confusion;  hallucinations (seeing, hearing, or feeling things that are not there);  mental depression 
  
  

• Rare
  • 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 may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Drowsiness 
  
  

• Less common
  • 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 taking this medicine, it may still produce some side effects that need attention. During this period of time check with your doctor if you notice the following side effect:

• More common
  • Diarrhea 
  
  

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

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.