Metyrapone (trade name Metopirone) is a drug used in the diagnosis of adrenal insufficiency and occasionally in the treatment of Cushing's syndrome (hypercortisolism).
Mechanism
Metyrapone blocks cortisol synthesis[1] by inhibiting steroid 11β-hydroxylase. This stimulates ACTH secretion, which in turn increases plasma 11-deoxycortisol levels.
Uses
Metyrapone can be used in the diagnosis of adrenal insufficiency. Metyrapone 30 mg/kg, maximum dose 3000 mg, is administered at midnight usually with a snack. The plasma cortisol and 11-deoxycortisol are measured the next morning between 8:00 and 9:00 am. A plasma cortisol less than 220 nmol/l indicates adequate inhibition of 11β-hydroxylase. In patients with intact Hypothalamo-pituitary-adrenal axis, CRH and ACTH levels rise as a response to the falling cortisol levels. This results in an increase of the steroid precursors in the pathway. Therefore if 11-deoxycortisol levels do not rise and remains less than 7 µg/dl and ACTH rises, then it is highly suggestive of impaired adrenal insufficiency, if neither 11-deoxycortisol nor ACTH rise it is highly suggestive of an impaired HPA axis at either the pituitary or hypothalamus.
Metyrapone test may aid in verifying the cause of Cushing's syndrome. Most patients with pituitary dysfunction and/or pituitary microadenoma will increase ACTH secretion in response to metyrapone, while most ectopic ACTH-producing tumors will not. Pituitary macroadenomas do not always respond to metyrapone.
Experimental use
Metyrapone has been found in early human trials to reduce recollection of emotional memories in normal volunteers. The volunteers showed significant impairment in ability to retrieve memories with negative emotional content while not impairing memories with neutral content. This has significant implication in the study of the process of emotional healing in post traumatic stress disorder.[2][3]
Due to the permissive action of cortisol on glucagon partial blockade of cortisol may reduce
the effects of circulating glucagon in chronically increasing blood glucose in Syndrome X / type 2 diabetes.
References
See also
External links
Huffington Post reports that Metyrapone may someday by used to manage PTSD by weakening those bad memories while keeping the good ones strong.
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| Mineralocorticoids
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no FG at 16) | |
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(3-one, 4-ene,
11-FG,
17-hydroxy) |
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noco (d)/cong/tumr, sysi/epon
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proc, drug (A10/H1/H2/H3/H5)
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