Formulary
Metyrapone: Indications, Dosing, Side Effects and Interactions
Metyrapone is a competitive inhibitor of 11-hydroxylation in the adrenal cortex; the resulting inhibition of cortisol (and to a lesser extent aldosterone)...
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Metyrapone: Indications, Dosing, Side Effects and Interactions
Metyrapone is a competitive inhibitor of 11-hydroxylation in the adrenal cortex; the resulting inhibition of cortisol (and to a lesser extent aldosterone)...
Drug action
Metyrapone is a competitive inhibitor of 11-hydroxylation in the adrenal cortex; the resulting inhibition of cortisol (and to a lesser extent aldosterone) production leads to an increase in ACTH production which, in turn, leads to increased synthesis and release of cortisol precursors. Metyrapone may be used as a test of anterior pituitary function.
Indications and dose
**Differential diagnosis of ACTH-dependent Cushing's syndrome (specialist supervision in hospital)**
- **Adult** (By Mouth): 750 mg every 4 hours for 6 doses.
**Management of Cushing's syndrome (specialist supervision in hospital)**
- **Adult** (By Mouth): Usual dose 0.25-6 g daily, dose to be tailored to cortisol production, dose is either low, and tailored to cortisol production, or high, in which case corticosteroid replacement therapy is also needed.
**Resistant oedema due to increased aldosterone secretion in cirrhosis, nephrotic syndrome, and congestive heart failure (with glucocorticoid replacement therapy) (specialist supervision in hospital)**
- **Adult** (By Mouth): 3 g daily in divided doses.
**Differential diagnosis of ACTH-dependent Cushing's syndrome (specialist supervision in hospital) for metyrapone**
- **Child** (By mouth): 15 mg/kg every 4 hours for 6 doses, alternatively 300 mg/m2 every 4 hours for 6 doses; usual dose 250-750 mg every 4 hours.
**Management of Cushing's syndrome (specialist supervision in hospital) for metyrapone**
- **Child** (By mouth): Usual dose 0.25-6 g daily, dose to be tailored to cortisol production, dose is either low, and tailored to cortisol production, or high, in which case corticosteroid replacement therapy is also needed.
Cautions
Avoid in Acute porphyrias ; gross hypopituitarism (risk of precipitating acute adrenal failure); hypertension on long-term administration; hypothyroidism (delayed response)
Contraindications
Adrenocortical insufficiency
Side effects
Common or very common Dizziness; headache; hypotension; nausea; sedation; vomiting Rare or very rare Abdominal pain; adrenal insufficiency; allergic dermatitis; hirsutism Frequency not known Alopecia; bone marrow failure; hypertension
Interactions
**Other interactions (5):**
- The interaction potential of metyrapone is partly unknown and therefore caution is advised when initiating and discontinuing treatment with other medicinal products.
- If changes to the effect and/or safety profile of metyrapone or the concomitant drug are seen, suitable action should be taken.
- Observed interactions In relation to use as a diagnostic aid: Anticonvulsants (e.g.
- If these drugs cannot be withdrawn, the necessity of carrying out the Metyrapone Esteve test should be reviewed.
- Anticipated interactions Metyrapone Esteve may potentiate paracetamol (acetaminophen) toxicity in humans.
Pregnancy
Avoid (may impair biosynthesis of fetal-placental steroids).
Breast feeding
Avoid-no information available.
Hepatic impairment
Manufacturer advises caution (risk of delayed response).
Medicinal forms
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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