Products
Metyrapone is commercially available in the form of capsules (Metopiron). It has been approved in many countries since 1961.
Structure and properties
Metyrapone (C14H14N2O, Mr = 226.27 g/mol) is a pyridine derivative. It is a white to light amber crystalline powder that is sparingly soluble in water.
Effects
Metyrapone (ATC V04CD01) inhibits the synthesis of corticosteroids in the adrenal cortex by inhibiting steroid 11beta-hydroxylase (CYP11B1). This enzyme converts 11-deoxycortisol to cortisol and 11-deoxycorticosterone to corticosterone. As a result, more ACTH is produced in the pituitary gland in the short term. Metyrapone also inhibits the synthesis of aldosterone and promotes renal excretion of sodium.
Indications
Metyrapone is used as a diagnostic agent to test the function of the anterior pituitary-adrenocortical axis. Therapeutically, it can be used as a 2nd-line agent in conditions associated with gluco- and mineralocorticoid (aldosterone) overproduction, such as Cushing’s syndrome or hyperaldosteronism,
Contraindications
For complete precautions, see the drug label.
Interactions
Drug-drug interactions are possible with antiepileptic drugs (phenytoin, barbiturates), antidepressants (e.g., amitriptyline, chlorpromazine), hormones, and thyrostatic drugs, among others. According to the scientific literature, it interacts with CYP450 and is an inducer of CYP3A.
Adverse effects
Nausea, vomiting, dizziness, fatigue, headache, and low blood pressure occur occasionally. Rarely, allergic skin reactions, adrenal insufficiency, hirsutism, and abdominal pain occur.
