Overview
11 DESCRIPTION Metopirone (metyrapone capsules) is an adrenal steroid synthesis inhibitor, available as 250‑mg capsules for oral administration. Its chemical name is 2‑methyl‑1, 2‑di‑3‑pyridyl‑1‑propanone, and its structural formula is Metyrapone is a white to light amber, fine, crystalline powder, having a characteristic odor.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The pharmacological effect of Metopirone is to reduce cortisol and corticosterone production by inhibiting the 11-beta-hydroxylation reaction in the adrenal cortex. Removal of the strong inhibitory feedback mechanism exerted by cortisol results in an increase in adrenocorticotropic hormone (ACTH) production by the pituitary. With continued blockade of the enzymatic steps leading to production of cortisol and corticosterone, there is a marked increase in adrenocortical secretion of their immediate precursors, 11-desoxycortisol and desoxycorticosterone, which are weak suppressors of ACTH release, and a corresponding elevation of these steroids in the plasma and of their metabolites in the urine.
Indications
- 1 INDICATIONS AND USAGE Metopirone is indicated, in combination with other diagnostic tests, for the diagnosis of adrenal insufficiency in adult and pediatric patients. Metopirone is indicated, in combination with other diagnostic tests, for the diagnosis of adrenal insufficiency in adult and pediatric patients. ( 1 )
Common Doses
- 30 mg
- 70 mcg
Dosage
2 DOSAGE AND ADMINISTRATION Single-Dose Short Test: 30 mg/kg at midnight ( 2.2 ) 2.1 Important Information Before Conducting Metopirone Testing Stop drugs affecting pituitary or adrenocortical function before administration of Metopirone in accordance with half-life of the drugs (consider at least 5 half-lives to avoid any interference with Metopirone testing). [see Drug Interactions (7.1) ] . Assess ability of patient's adrenals to respond to exogenous ACTH before Metopirone is employed as a test [see Warnings and Precautions (5.1) ] . 2.
Contraindications
- 4 CONTRAINDICATIONS Metopirone is contraindicated in patients with adrenal cortical insufficiency or hypersensitivity to Metopirone or to any of its excipients. In patients with adrenal cortical insufficiency ( 4 ) Hypersensitivity to Metopirone or to any of its excipients ( 4 )
Side Effects
- 6 ADVERSE REACTIONS The following adverse reactions associated with the use of Metopirone were identified in clinical trials or postmarketing reports. Because these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cardiovascular System: Hypotension Gastrointestinal System: Nausea, vomiting, abdominal discomfort or pain Central Nervous System: Headache, dizziness, sedation Dermatologic System: Allergic rash Hematologic System: Leukopenia, anemia, and/or...
Interactions
- 7 DRUG INTERACTIONS Anticonvulsants, psychotropic, hormone preparations, corticosteroids, antithyroid agents, cyproheptadine: may affect the results of the metyrapone test. ( 7.1 ) Acetaminophen: Avoid concomitant use with Metopirone. ( 7.2 ) 7.1 Effect of Other Drugs on Metopirone Anticonvulsants, psychotropic drugs, hormone preparations, corticosteroids, antithyroid agents and cyproheptadine may affect the results of the Metopirone test. If these drugs cannot be withdrawn, the necessity of carrying out the Metopirone test should be reviewed. 7.