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Details with Side Effects
Megestrol acetate may cause fetal harm when administered to a pregnant woman. For animal data on fetal effects, see PRECAUTIONS: Carcinogenesis, Mutagenesis, Impairment of Fertility: Impairment of Fertility. There are no adequate and well-controlled studies in pregnant women. If this drug is used during pregnancy, or if the patient becomes pregnant while taking (receiving) this drug, the patient should be apprised of the potential hazard to the fetus. Women of childbearing potential should be advised to avoid becoming pregnant.
Megestrol acetate is not intended for prophylactic use to avoid weight loss. (See also PRECAUTIONS: Carcinogenesis, Mutagenesis, Impairment of Fertility.)
The glucocorticoid activity of MEGACE (megestrol acetate, USP) Oral Suspension has not been fully evaluated. Clinical cases of new onset diabetes mellitus, exacerbation of preexisting diabetes mellitus, and overt Cushing's syndrome have been reported in association with the chronic use of MEGACE. In addition, clinical cases of adrenal insufficiency have been observed in patients receiving or being withdrawn from chronic MEGACE therapy in the stressed and non-stressed state. Furthermore, adrenocorticotropin (ACTH) stimulation testing has revealed the frequent occurrence of asymptomatic pituitary-adrenal suppression in patients treated with chronic MEGACE therapy. Therefore, the possibility of adrenal insufficiency should be considered in any patient receiving or being withdrawn from chronic MEGACE therapy who presents with symptoms and/or signs suggestive of hypoadrenalism (e.g., hypotension, nausea, vomiting, dizziness, or weakness) in either the stressed or non-stressed state. Laboratory evaluation for adrenal insufficiency and consideration of replacement or stress doses of a rapidly acting glucocorticoid are strongly recommended in such patients. Failure to recognize inhibition of the hypothalamic-pituitary-adrenal axis may result in death. Finally, in patients who are receiving or being withdrawn from chronic MEGACE therapy, consideration should be given to the use of empiric therapy with stress doses of a rapidly acting glucocorticoid in conditions of stress or serious intercurrent illness (e.g., surgery, infection).
Therapy with MEGACE Oral Suspension for weight loss should only be instituted after treatable causes of weight loss are sought and addressed. These treatable causes include possible malignancies, systemic infections, gastrointestinal disorders affecting absorption, endocrine disease, and renal or psychiatric diseases.
Effects on HIV viral replication have not been determined.
Use with caution in patients with a history of thromboembolic disease.
Use in Diabetics
Exacerbation of preexisting diabetes with increased insulin requirements has been reported in association with the use of MEGACE.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Data on carcinogenesis were obtained from studies conducted in dogs, monkeys, and rats treated with megestrol acetate at doses 53.2, 26.6, and 1.3 times lower than the proposed dose (13.3 mg/kg/day) for humans. No males were used in the dog and monkey studies. In female beagles, megestrol acetate (0.01, 0.1, or 0.25 mg/kg/day) administered for up to 7 years induced both benign and malignant tumors of the breast. In female monkeys, no tumors were found following 10 years of treatment with 0.01, 0.1, or 0.5 mg/kg/day megestrol acetate. Pituitary tumors were observed in female rats treated with 3.9 or 10 mg/kg/day of megestrol acetate for 2 years. The relationship of these tumors in rats and dogs to humans is unknown but should be considered in assessing the risk-to-benefit ratio when prescribing MEGACE Oral Suspension and in surveillance of patients on therapy. (See WARNINGS.)
No mutagenesis data are currently available.
Impairment of Fertility
Perinatal/postnatal (segment III) toxicity studies were performed in rats at doses (0.05–12.5 mg/kg) less than that indicated for humans (13.3 mg/kg); in these low dose studies, the reproductive capability of male offspring of megestrol acetate-treated females was impaired. Similar results were obtained in dogs. Pregnant rats treated with megestrol acetate showed a reduction in fetal weight and number of live births, and feminization of male fetuses. No toxicity data are currently available on male reproduction (spermatogenesis).
Pregnancy Category X. (See WARNINGS and PRECAUTIONS: Carcinogenesis, Mutagenesis, Impairment of Fertility: Impairment of Fertility.) No adequate animal teratology information is available at clinically relevant doses.
Because of the potential for adverse effects on the newborn, nursing should be discontinued if MEGACE Oral Suspension is required.
Use in Women
Breakthrough bleeding was observed in all 10 female patients participating in the clinical trials. Megace is a progesterone derivative, which may induce vaginal bleeding in women.
Safety and effectiveness in pediatric patients have not been established.
Clinical studies of MEGACE Oral Suspension in the treatment of anorexia, cachexia, or an unexplained, significant weight loss in patients with AIDS did not include sufficient numbers of patients aged 65 years and older to determine whether they respond differently than younger patients. Other reported clinical experience has not identified differences in responses between elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
Megestrol acetate is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.
Last reviewed on RxList: 4/19/2012
This monograph has been modified to include the generic and brand name in many instances.
Additional Megace Information
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