Megestrol Acetate

Indications
Megestrol Acetate is used in anorexia, cachexia or a significant weight loss. Megestrol Acetate is also indicated for the palliative treatment of advanced carcinoma of the breast (i.e. recurrent, inoperable or metastatic diseases). It should not be used in lieu of currently accepted procedures such as surgery, radiation or chemotherapy.

Therapeutic Class
Hormonal Chemotherapy

Pharmacology
Megestrol Acetate is a synthetic progestational anticancer drug. It may work by interfering with the hormone balance in the body, which may stop the cancer growing. It may also act directly on cancer cells so that they can't grow. Moreover, Megestrol Acetate causes weight gain by increasing the fat and body cell mass and this weight gain is associated with increased appetite. Therefore this drug is used as an appetizer for the cancer patients suffering from anorexia, significant weight loss or cachexia.

Dosage & Administration
For the following indications, at least two months of continuous treatment is considered an adequate period for determining the efficacy of megestrol acetate tablets.
For palliative or adjunctive treatment of breast carcinoma: 160 mg or 125 mg/m² daily (40 mg q.i.d. or 160 mg q.d.)
For endometrial carcinoma: 80 - 320 mg or 62.5 - 250 mg/m² daily in divided doses (40 - 80 mg one to four times daily or one to two 160 mg tablets daily).
For palliative treatment of hormone responsive advanced (Stage D2) carcinoma of the prostate: 120 mg (93.8 mg/m²) as a single daily dose in combination with diethylstilbestrol tablet, 0.1 mg.
For anorexia, cachexia, or significant weight loss in patients with cancer: usual adult dose: 400 to 800 mg as a single daily dose.
The recommended adult initial dosage of megestrol acetate oral suspension is 625 mg/day (5 mL/day or one teaspoon daily). Shake container well before using

Interaction
Concentrations of indinavir may be reduced. Possible reduced efficacy of cisplatin. Warfarin half life may be increased. Megestrol concentration may be decreased by aminoglutethimide and enzyme-inducing drugs.

Contraindications
Allergy to Megestrol acetate or any of the excipients. Women of child bearing potential should be advised to avoid becoming pregnant.

Side Effects
Side Effects: Nausea, vomiting, edema occur in approximately 1% to 2% of patients. Dyspnea, pain, hypertension, hot flashes, sweating mood changes, hyperglycemia, alopecia, asthenia, malaise, lethargy, rash, flatulence, diarrhoea and impotence have been reported. Constipation and urinary frequency have been reported in patients who received high doses of Megestrol acetate in clinical trials.
Adverse effects:
Thromboembolic phenomena: Thromboembolic phenomena including thrombophlebitis and pulmonary embolism (in some cases fatal) have been reported.
Other adverse reactions: Breakthrough uterine bleeding occur in approximately 1% to 2% of patients. Heart failure, cushingoid facies, tumor flare (with or without hypercalcemia), carpal tunnel syndrome and urticaria have been reported.

Pregnancy & Lactation
Pregnancy category D. Megestrol Acetate can cause fetal abnormalities and risks, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits.
Nursing mothers: Very small amounts (approximately 0.1%) are excreted in mother's milk. It is however, not known whether these amounts exert any harmful effect on the newborn. Because of the potential for adverse effects on the new born, nursing should be discontinued during treatment with Megestrol Acetate.

Precautions & Warnings
History of thrombophlebitis, mild to moderate hepatic impairment, risk of fluid retention, history of depression, diabetes, hypertension, renal or cardiac dysfunction.

Use in Special Populations
Pediatric use: The safety and efficacy of Megestrol Acetate has not been established in pediatric cases. In general, dose selection for a pediatric patient should be cautious.
Geriatric use: Insufficient data from clinical studies of Megestrol acetate are available for patients 65 years of age and older to determine whether they respond differently than younger patients. In general, dose selection for an elderly patient should be cautious.
Hepatic impairment: Dose selection for a hepatic impaired patient should be cautious.
Renal impairment: Dose selection for a renal impaired patient should be cautious.