| Item |
Information |
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Drug Groups
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approved |
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Description
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An inhibitor of the enzyme steroid 11-beta-monooxygenase. It is used as a test of the feedback hypothalamic-pituitary mechanism in the diagnosis of cushing syndrome. [PubChem] |
| Indication |
Used as a diagnostic drug for testing hypothalamic-pituitary ACTH function. Occasionally used in Cushing's syndrome. |
| Pharmacology |
Metopirone is an inhibitor of endogenous adrenal corticosteroid synthesis. |
| Toxicity |
Oral LD50 in rats is 521 mg/kg. One case has been recorded in which a 6-year-old girl died after two doses of Metopirone, 2 g. Symptoms of overdose include cardiac arrhythmias, hypotension, dehydration, anxiety, confusion, weakness, impairment of consciousness, nausea, vomiting, epigastric pain, and diarrhea. |
| Affected Organisms |
| • |
Humans and other mammals |
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| Biotransformation |
Hepatic. The major biotransformation is reduction of the ketone to metyrapol, an active alcohol metabolite. Metyrapone and metyrapol are both conjugated with glucuronide. |
| Absorption |
Absorbed rapidly and well when administered orally. Peak plasma concentrations are usually reached 1 hour after administration. |
| Half Life |
1.9 ±0.7 hours. |
| Elimination |
After administration of 4.5 g metyrapone (750 mg every 4 hours), an average of 5.3% of the dose was excreted in the urine in the form of metyrapone (9.2% free and 90.8% as glucuronide) and 38.5% in the form of metyrapol (8.1% free and 91.9% as glucuronide) within 72 hours after the first dose was given. |
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