metyrapone at a glance
Medicine class
Steroidogenesis inhibitor and diagnostic agent for pituitary function.
Main treatment role
Lowers excessive cortisol in endogenous Cushing’s syndrome.
Monitoring
Cortisol, potassium and blood pressure require monitoring; ECG assessment may be appropriate when cardiac risk is relevant.
What is metyrapone used for?
Uses include:
Management of endogenous Cushing’s syndrome.
A diagnostic aid when assessing ACTH insufficiency.
Helping distinguish ACTH-dependent causes of Cushing’s syndrome.
Treatment alongside a glucocorticoid for resistant oedema associated with increased aldosterone secretion in cirrhosis, nephrosis or congestive heart failure.
How does metyrapone work?
Metyrapone inhibits adrenal 11β-hydroxylase, reducing production of cortisol and, to a lesser extent, aldosterone. The resulting rise in ACTH and 11-deoxycortisol is used in pituitary–adrenal testing; sustained cortisol reduction is its therapeutic effect in Cushing’s syndrome.
metyrapone preparations and strengths
Capsule
Route: Oral
Strengths: 250 mg
How to take metyrapone
Follow the specialist’s instructions and do not alter or stop treatment independently.
Swallow the soft capsules whole; do not chew them.
Take with milk or after a meal to reduce nausea and vomiting.
Diagnostic testing is performed under healthcare supervision and may require hospital attendance.
Do not drive or operate machinery if you feel dizzy, tired or drowsy.
metyrapone side effects
Common or expected effects
- Nausea, abdominal pain or diarrhoea
- Reduced appetite
- Headache or dizziness
- Tiredness or weakness
- High blood pressure
- Skin rash, itching or hives
- Joint pain or peripheral swelling
- Acne, increased hair growth or muscle pain
Get urgent medical advice
- Symptoms of adrenal insufficiency, including pronounced weakness, dizziness, vomiting, diarrhoea, abdominal pain, low blood pressure or faintness
- Severe allergic reaction
- Unusual or prolonged bleeding or bruising
- Fever with shortness of breath, particularly in severe Cushing’s syndrome
- Palpitations, fainting or other symptoms suggesting an abnormal heart rhythm
metyrapone in pregnancy
Metyrapone is not generally recommended for diagnostic testing or treatment during pregnancy unless a specialist judges that the potential benefit outweighs the risks. It crosses the placenta; if exposure is necessary, maternal blood pressure and the newborn’s cortisol and electrolytes require specialist monitoring.
metyrapone while breastfeeding
Information about transfer into human milk is insufficient and risk to the infant cannot be excluded. Product information advises stopping breastfeeding during treatment; discuss feeding options with the specialist team.
metyrapone interactions
The overall interaction profile is not fully characterised. Tell the specialist about all prescribed, over-the-counter and herbal products, particularly before diagnostic testing.
Paracetamol
Metyrapone may increase paracetamol toxicity; obtain medical or pharmacist advice before using them together.
Anticonvulsants such as phenytoin or barbiturates
They may alter the result of a metyrapone diagnostic test.
Antidepressants, antipsychotics and related medicines
Medicines including amitriptyline, chlorpromazine and alprazolam may affect diagnostic-test results.
Common questions about metyrapone
Answers are fully visible for fast scanning and source review.
Why is metyrapone used for Cushing’s syndrome?
It inhibits adrenal cortisol synthesis, helping reduce excessive cortisol in endogenous Cushing’s syndrome.
How does metyrapone test pituitary and adrenal function?
It lowers cortisol production, which should trigger ACTH release and increase 11-deoxycortisol when the pituitary–adrenal response is intact.
Can metyrapone make cortisol too low?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.