Side Effects of Megace (megestrol)

Megace (megestrol) is a synthetic form of progesterone, a female hormone used to stimulate appetite in patients with AIDS who have poor appetite or an unexplained significant weight loss.

Megace is also used to treat breast cancer and weight loss associated with cancer. Progesterone is a hormone produced by the body, especially in women, that helps control the menstrual period as well as other body functions. How Megace stimulates appetite or suppresses cancer is not understood. 

Common side effects of Megace include

• diarrhea,
• weight gain,
• nausea,
• rash,
• impotence,
• insomnia,
• mood swings,
• sweating,
• breakthrough menstrual bleeding,
• high blood pressure (hypertension), and
• excess gas (flatulence).

Serious side effects of Megace include

• blood clots in legs and lungs and
• worsening of existing diabetes or new onset diabetes.

Drug interactions of Megace include indinavir, which reduces blood concentrations of Megace. An increase in the dose of Megace should be considered.

Megace may cause birth defects and should not be administered to pregnant women. Women should use contraception while taking Megace.

Megace should not be used while breastfeeding due to potential adverse effects in the infant.

The most common side effects are:

• diarrhea,
• weight gain,
• nausea,
• rash,
• impotency,
• insomnia,
• mood swings,
• sweating,
• breakthrough menstrual bleeding,
• high blood pressure, and
• excess gas (flatulence).

Blood clots in legs and lungs may occur.

Megestrol may worsen existing diabetes or lead to new onset diabetes.

Clinical Adverse Events

Adverse events which occurred in at least 5% of patients in any arm of the two clinical efficacy trials and the open trial are listed below by treatment group. All patients listed had at least one post baseline visit during the 12 study weeks. These adverse events should be considered by the physician when prescribing Megace Oral Suspension.

ADVERSE EVENTS % of Patients Reporting

Adverse events which occurred in 1% to 3% of all patients enrolled in the two clinical efficacy trials with at least one follow-up visit during the first 12 weeks of the study are listed below by body system. Adverse events occurring less than 1% are not included. There were no significant differences between incidence of these events in patients treated with megestrol acetate and patients treated with placebo.

Body as a Whole: abdominal pain, chest pain, infection, moniliasis and sarcoma

Cardiovascular System: cardiomyopathy and palpitation

Digestive System: constipation, dry mouth, hepatomegaly, increased salivation and oral moniliasis

Hemic and Lymphatic System: leukopenia

Metabolic and Nutritional: LDH increased, edema and peripheral edema

Nervous System: paresthesia, confusion, convulsion, depression, neuropathy, hypesthesia and abnormal thinking

Respiratory System: dyspnea, cough, pharyngitis and lung disorder

Skin and Appendages: alopecia, herpes, pruritus, vesiculobullous rash, sweating and skin disorder

Special Senses: amblyopia

Urogenital System: albuminuria, urinary incontinence, urinary tract infection and gynecomastia

Postmarketing

Postmarketing reports associated with Megace Oral Suspension include thromboembolic phenomena including thrombophlebitis and pulmonary embolism, and glucose intolerance.

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. The effects of zidovudine or rifabutin on the pharmacokinetics of megestrol acetate were not studied.

Megestrol acetate may interact with warfarin and increase International Normalized Ratio (INR). Closely monitor INR in patients taking MEGACE and warfarin.