L02AB02 - Medroxyprogesterone |
Probably porphyrinogenic |
PRP |
Rationale
Progestagenic effects in general are recognized to be strongly porphyrogenic. No published reports of attacks of acute porphyria connected with exposure to medroxyprogesterone. The substance is listed as inducer of CYP3A4, but there is no clinical evidence supporting significant potency.
Chemical description
Medroxyprogesterone acetate is a synthetic progestin, a derivative of 17 α-hydroxyprogesterone that differs structurally by the addition of a 6 α-methyl group and a 17 α-acetate group.
Therapeutic characteristics
Medroxyprogesterone is indicated for the treatment of certain hormone dependant neoplasms, such as endometrial carcinoma, renal cell carcinoma, or carcinoma of breast in post menopausal women. It is also used for the treatment of menorrhagia, secondary amenorrhoea, endometriosis or as a contraceptive. It is given orally or, for prolonged action, as an aqueous suspension by intramuscular or subcutaneous injection.
Metabolism and pharmacokinetics
Medroxyprogesterone acetate is metabolised in the liver. It is oxidatively metabolized in the liver to hydroxy derivative and excreted in urine and bile after conjugation. Listed as substrate (Rendic, 2002; Zhou, 2007) and weak inducer of CYP 3A4 (Zhou, 2007). Medroxyprogesterone was found to be a moderate inhibitor of CYP2C9 and weak inhibitor of CYP3A4, but is not a mechanism based-inhibitor (Zhang, 2006).
Published experience
A low dose (10 mg) of medroxyprogesterone was used in combination with the GnRH agonist buserelin for the treatment of premenstrual attacks of porphyria in one AIP woman and one VP woman, the women did not experience any attacks during this treatment (Bargetzi, 1989).
References
- Scientific articles
- Rendic, S. Summery of information on human CYP enzymes: human P450 metabolism. Drug metabolism reviews 2002; 34(1&2), 83-448. #1025
- Zhou, S.F., Xue, C.C., et al. Clinically important drug interactions potentially involving mechanism-based inhibition of cytochrome P450 3A4 and the role of therapeutic drug monitoring. Ther Drug Monit 2007; 29(6):687:710. #1027
- Bargetzi MJ, Meyer UA, et al. Premenstrual exacerbations in hepatic porphyria: prevention by intermittent administration of an LH-RH agonist in combination with a gestagen. JAMA. 1989;261(6):864. PMID 2492353. #4589
- Zhang JW, Liu Y, et al. Inhibitory effect of medroxyprogesterone acetate on human liver cytochrome P450 enzymes. Eur J Clin Pharmacol. 2006;62(7):497-502. Epub 2006 Apr 28. PMID 16645869. #4590
- Drug reference publications
- McEvoy GK, editor. Medroxyprogesterone. The AHFS Drug Information 2008. Bethesda, MD: American Society of Health-System Pharmacists; 2009. Electronic version (30.07.10). #2128
- Sweetman SC, editor. Martindale: The complete drug reference. Medroxyprogesterone. Pharmaceutical Press 2009. #2129
- Summary of Product Characteristics
- The electronic Medicines Compendium (emc). Summary of Product Characteristics (SPC). Provera Tablets. #2130
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