In the U.S.—

In Canada—

• Antiadrenal
• Diagnostic aid, pituitary function

Metyrapone ( me-TEER-a-pone) is used in the diagnosis of certain problems of the adrenal glands. These glands are located near the kidneys. The adrenal glands produce a steroid chemical called cortisol (hydrocortisone) that helps the body respond to stress or illness. From the results of a metyrapone test, your doctor will be able to tell if your adrenal glands produce the correct amount of cortisol under stress or during illnesses.

How test is done: Metyrapone is taken by mouth in one or more doses the day before the testing is done. The next day, blood and/or urine samples are taken. A tube called a catheter may be placed in your bladder to help take the urine sample. The amount of hormones in your blood or urine is measured. Then the results of the test are studied.

Metyrapone may also be used for other conditions as determined by your doctor.

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

Oral
• Tablets (U.S. and Canada)

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 metyrapone, the following should be considered:

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

Pregnancy—Metyrapone has not been fully studied in pregnant women. However, some small studies have shown that metyrapone can affect the production of chemicals by the pituitary and adrenal glands of the fetus. Also, the large amounts of estrogen produced by your body during pregnancy may cause false results in metyrapone testing. Before you take metyrapone, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—It is not known whether metyrapone passes into the breast milk. However, use of metyrapone is not recommended during breast-feeding because it may cause unwanted effects in nursing babies.

Children—This medicine has been tested in children and has not been shown to cause different side effects or problems in children than it does in adults.

Older adults—Although there is no specific information about the use of metyrapone in the elderly, it is not expected to cause different side effects or problems in older people than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases 2 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. When you are taking metyrapone, it is especially important that your health care professional know if you are also taking any other medicines, since many medicines can cause false results in metyrapone testing. This may result in a wrong diagnosis. It is especially important that your doctor know if you are taking any of the following:

• Alcohol (with chronic use)
• Barbiturates
• Carbamazepine (e.g., Tegretol)
• Corticosteroids (cortisone-like medicine)
• Estrogens (female hormones)
• Griseofulvin (e.g., Fulvicin)
• Oral contraceptives (birth control pills) containing estrogen
• Phenylbutazone (e.g., Butazolidin)
• Phenytoin (e.g., Dilantin)
• Primidone (e.g., Mysoline)
• Rifampin (e.g., Rifadin)

• Breast cancer or
• Diabetes mellitus (sugar diabetes) or
• Heart disease or
• Liver disease or
• Low blood sugar or
• Thyroid disease—These conditions may cause false results in metyrapone testing and result in a wrong diagnosis

• Excessive body hair in females—Long-term use may increase growth of body hair

• Porphyria—Metyrapone may worsen active cases of porphyria

• Underactive adrenal or pituitary gland—Metyrapone may severely reduce the amount of certain hormones produced by the adrenal glands; these hormones are needed to respond to stress or illness

Metyrapone may cause nausea and vomiting, especially if taken in larger doses. Taking each dose with food or milk or immediately after eating may lessen this effect.

Before you have any medical tests, tell the doctor in charge that you are taking this medicine. The results of some tests may be affected by this medicine.

Dosing—

The dose of metyrapone will be different for different patients. Follow your doctor's orders. The dose will be given by your doctor. The following information includes only the average doses of metyrapone.

• For tablet dosage form:
  • For testing the adrenal glands:
    • Adults—750 milligrams (mg) (3 tablets) every four hours for six doses. Or, your doctor may want you to take 2000 to 3000 mg (8 to 12 tablets) as a single dose at eleven p.m.
    • Children—Dose is based on body weight and must be determined by your doctor. The usual dose is 15 mg per kilogram (kg) (6.8 mg per pound) of body weight every four hours for six doses.

Missed dose—

If you are taking metyrapone every day to treat Cushing's syndrome and you miss a dose, 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. If you are taking metyrapone for a test procedure and you miss a dose, contact your physician. Missing doses or taking them on the wrong schedule may cause false test results.

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.

This medicine may cause some people to become dizzy, lightheaded, drowsy, or less alert than they are normally. Even if taken at bedtime, it may cause some people to feel drowsy or less alert on arising. 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 dizzy or 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 immediately if any of the following side effects occur:

• Rare (with long-term use)
  • Irregular heartbeat 
  
  

Check with your doctor as soon as possible if any of the following side effects occur:

• Less common
  • Skin rash 
  
  

• Rare (usually with long-term use)
  • Enlargement of clitoris;  muscle cramps or pain;  sore throat or fever;  swelling of feet or lower legs;  unusual bleeding or bruising;  unusual tiredness or weakness;  weight gain (rapid) 
  
  

• Symptoms of overdose
  • Abdominal or stomach pain (severe);  confusion;  decrease in consciousness;  diarrhea (severe);  nausea (severe);  nervousness;  unusual thirst;  vomiting (severe);  weakness (sudden)  
  
  

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
  • Dizziness;  drowsiness;  headache;  lightheadedness;  nausea 
  
  

• Rare
  • Confusion or mental slowing;  excessive hair growth;  greater-than-normal loss of scalp hair ;  increased sweating;  loss of appetite;  upper abdominal or stomach pain;  vomiting;  worsening of acne 
  
  

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

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although this use is not included in product labeling, metyrapone is used in certain patients with the following medical condition:

• Cushing's syndrome (diagnosis and treatment)

Since treatment for Cushing's syndrome may require longer therapy, side effects are more likely to occur.