What is Metypirom used for?

Metypirom is used as a diagnostic test to help doctors find out if a patient has adrenal insufficiency.

Can Metypirom cause dizziness?

Yes, Metypirom may cause dizziness and sleepiness, so you should not drive or operate machinery until these effects go away.

Is it safe to take Tylenol with Metypirom?

No, you should avoid taking acetaminophen with Metypirom because it can increase the risk of acetaminophen side effects.

Can Metypirom be used during pregnancy?

Metypirom can pass to the baby and may lower fetal cortisol levels; there is not enough information to rule out risks.

What should I do if I feel nauseous after taking Metypirom?

Nausea and vomiting are known side effects; contact your healthcare provider if symptoms are severe.

Can children take Metypirom?

Yes, Metypirom is indicated for diagnosing adrenal insufficiency in pediatric patients.

What are the signs of an overdose of Metypirom?

Signs include stomach pain, nausea, vomiting, low blood pressure, confusion, and weakness.

Who should NOT take Metypirom?

People with adrenal cortical insufficiency or anyone allergic to the ingredients should not take it.

Metyrapone | CAS 54-36-4 | FJLBFSROUSIWMA

Loading compound...

Adrenal steroid synthesis inhibitor (Diagnostic Aid)

Metypirom (metyrapone) is a medication used as a diagnostic tool to help identify adrenal insufficiency in both adults and children. It works by temporarily blocking the production of certain hormones, which allows doctors to see how the pituitary gland responds. Because it can cause sudden changes in hormone levels, it is typically used under medical supervision, often in a hospital setting.

How it worksMetypirom works by blocking a specific step in how your body makes cortisol. When cortisol levels drop, your pituitary gland tries to compensate by producing more ACTH (adrenocorticotropic hormone), which helps doctors test how well your glands are functioning.

Brand names:METOPIRONE

Used for

Diagnosing adrenal insufficiency in adultsDiagnosing adrenal insufficiency in children

Conditions

Adrenal insufficiency

Class

Adrenal steroid synthesis inhibitorDiagnostic AidAdrenal steroid synthesis inhibitor (Diagnostic Aid)Endocrine systemGastrointestinal systemCentral nervous systemCardiovascular systemHematologic system

How to take

FormsOral capsule

RoutesOral

For the single-dose short test, the dose is 30 mg/kg (up to a maximum of 3 grams) taken at midnight with a snack, milk, or yogurt.

The test is usually done by an outpatient, but people suspected of having adrenal insufficiency may need to stay in the hospital overnight for safety.

Key warnings

·Metypirom can cause a sudden, dangerous drop in adrenal hormone production.
·It may cause dizziness or sleepiness; do not drive or use machinery until these effects pass.
·Doctors must ensure your adrenal glands can respond to ACTH before starting the test.

Do not use if

·People who already have adrenal cortical insufficiency.
·People who are allergic to Metypirom or any of its ingredients.

Side effects

Common

NauseaVomitingStomach pain or discomfortHeadacheDizzinessSleepiness (sedation)Low blood pressure (hypotension)Allergic rash

Serious

·Acute adrenal insufficiency (sudden drop in hormone production)
·Low blood cell counts (anemia, low white blood cells, or low platelets)
·Heart rhythm changes (arrhythmias)
·Severe dehydration

Seek help if

·Allergic rash
·Severe stomach pain
·Confusion or weakness
·Heart palpitations

Interactions

·Acetaminophen (Tylenol): Avoid using this with Metypirom because Metypirom can make it harder for your body to get rid of acetaminophen, increasing the risk of side effects.
·Anticonvulsants, psychoactive drugs, hormone preparations, corticosteroids, and anti-thyroid drugs: These may change the results of the Metypirom test.
·Cyproheptadine: May affect the test results.

FoodThe recommended dose should be taken at midnight with milk, yogurt, or a snack.

Special populations

PregnancyMetypirom can pass through the placenta to the baby and may lower the baby's cortisol production. There is not enough data to confirm if it causes major birth defects, but it can affect the hormone production of the fetus.

PediatricMetypirom is used in children to help diagnose adrenal insufficiency when used with other diagnostic tests.

GeriatricThere isn't enough specific information from studies on people 65 and older to know if they react differently than younger adults.

Talk to your doctor

Monitor

·Dizziness and sedation levels
·Blood pressure
·Signs of acute adrenal insufficiency
·Blood cell counts (anemia, leukopenia, thrombocytopenia)

Questions to ask

·Is my adrenal function strong enough for this test?
·Should I stop my other medications before the Metypirom test?
·Do I need to stay in the hospital overnight for this test?

Pharmacokinetics

OnsetPeak plasma concentration occurs approximately 1 hour after oral administration.

Half-lifeMetyrapon has a half-life of about 1.9 hours; its active metabolite metyrapol has a half-life of about 4 hours.

DurationThe ratio of metyrapon to its metabolite is 1:1.5 after eight hours.

MetabolismMetyrapon is reduced to an active alcohol metabolite called metyrapol.

ExcretionApproximately 5.3% of the dose is excreted in urine following a 750 mg dose every 4 hours.

Practical

OverdoseAn overdose can cause stomach issues, low blood pressure, heart rhythm problems, anxiety, confusion, and signs of sudden adrenal failure. Death has been reported in a child following a high dose.

StorageStore at room temperature between 68°F and 77°F. Keep the container tightly closed and protected from heat and moisture.

Ingredients

Allergens

gelatin

Inactive

Ethyl vanillingelatinglycerolmacrogol 400macrogol 4000paramethoxy acetophenonepurified watersodium ethyl parahydroxybenzoatesodium propyl parahydroxybenzoatetitanium dioxidealuminum chloride hexahydratecarminic acidhypromellosepropylene glycolsodium hydroxide

Educational summary derived from FDA labeling, AI-assisted. Not medical advice — consult a healthcare professional. Updated 2026-04-25.