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Active ingredient: Megestrol - Brands, Medical Use, Clinical Data

Brands, Medical Use, Clinical Data

Drug Category

  • Antineoplastic Agents, Hormonal
  • Contraceptives, Oral, Synthetic

Dosage Forms

  • Oral suspension containing 125 mg of megestrol acetate per mL
  • Tablet

Brands / Synonyms

DMAP; Ethinyl estradiol; Magestin; Maygace; Megace; Megace ES; Megeron; Megestat; Megestil; Megestin; Megestrol; Megestrol Acetate; Megestrolo [DCIT]; Megestrolum [INN-Latin]; Megestryl acetate; MGA; Nia; Niagestin; Ovaban; Ovarid; Volidan


For the treatment of anorexia, cachexia, or an unexplained, significant weight loss in patients with a diagnosis of acquired immunodeficiency syndrome (AIDS). Also used to treat breast cancer, endometrial cancer, and prostate cancer in Canada and some other countries.


Megestrol is a synthetic progestin and has the same physiologic effects as natural progesterone. The precise mechanism of megestrol’s antianorexic and anticachetic effects is unknown. Initially developed as a contraceptive, it was first evaluated in breast cancer treatment in 1967.

Mechanism of Action

Several investigators have reported on the appetite enhancing property of megestrol acetate and its possible use in cachexia. The precise mechanism by which megestrol acetate produces effects in anorexia and cachexia is unknown at the present time. The biochemical mechanism of progestin antitumour activity is not well but may involve interaction with progesterone and glucocorticoid receptors, androgenic properties. Megestrol also has direct cytotoxic effects on breast cancer cells in tissue culture and suppresses luteinising hormone release from the pituitary.


Variable, but well absorbed orally.


No serious unexpected side effects have resulted from studies involving megestrol acetate oral suspension administered in dosages as high as 1200 mg/day.

Biotrnasformation / Drug Metabolism

Primarily hepatic. Megestrol metabolites which were identified in urine constituted 5% to 8% of the dose administered. Respiratory excretion as labeled carbon dioxide and fat storage may have accounted for at least part of the radioactivity not found in urine and feces. No active metabolites have been identified.


History of hypersensitivity to megestrol acetate or any component of the formulation. Known or suspected pregnancy.

Drug Interactions

Pharmacokinetic studies show that there are no significant alterations in pharmacokinetic parameters of zidovudine or rifabutin to warrant dosage adjustment when megestrol acetate is administered with these drugs. A pharmacokinetic study demonstrated that coadministration of megestrol acetate and indinavir results in a significant decrease in the pharmacokinetic parameters (~36% for Cmax and ~28% for AUC) of indinavir. Administration of a higher dose of indinavir should be considered when coadministering with megestrol acetate. The effects of indinavir, zidovudine or rifabutin on the pharmacokinetics of megestrol acetate were not studied.

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