Megace (Megestrol Acetate)

• Megestrol acetate (Megace) is employed as an appetite stimulant and antineoplastic agent across several disease groups.
• Cachexia / weight loss associated with cancer or AIDS: improves appetite and promotes weight gain.
• Anorexia: stimulates food intake and helps maintain nutritional status.
• Advanced breast cancer: provides hormonal antineoplastic activity that can slow disease progression.
• Endometrial cancer: used as hormonal therapy to control tumour growth.

• Megestrol acetate is a synthetic progestogen that binds to progesterone receptors, exerting hormonal effects that modulate gene transcription. Its glucocorticoid‑like activity influences metabolic pathways, leading to increased appetite and weight gain, while also inhibiting estrogen‑driven tumour proliferation in hormone‑sensitive cancers.

Megestrol acetate may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Nausea or vomiting
• Weight gain and fluid retention
• Edema of the extremities
• Fatigue or weakness
• Hot flashes or sweating
• Mild hypertension

Serious or Rare Side Effects

• Thromboembolic events (deep vein thrombosis, pulmonary embolism)
• Adrenal insufficiency or suppression
• Severe hyperglycaemia or new‑onset diabetes
• Cushingoid syndrome (moon face, central obesity)
• Hepatic dysfunction or jaundice
• Anaphylactic or severe allergic reactions

Before initiating therapy, clinicians should evaluate several safety aspects.

• Monitor blood glucose: assess for hyperglycaemia, especially in diabetic patients.
• Assess thromboembolic risk: avoid in patients with recent clotting events.
• Evaluate liver function: check hepatic enzymes periodically.
• Contraindicated in pregnancy: teratogenic risk (Category X).
• Use caution in cardiovascular disease: monitor blood pressure and fluid status.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Megestrol acetate can alter the activity of several concomitant medicines.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole) may increase drug exposure.
• Anticoagulants (e.g., warfarin) can heighten bleeding risk.
• Antidiabetic agents (insulin, sulfonylureas) may require dose reduction due to hyperglycaemia.
• HIV protease inhibitors may affect hormone metabolism.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin) may reduce efficacy.
• Systemic corticosteroids can augment glucocorticoid‑related effects.
• Non‑steroidal anti‑inflammatory drugs may increase risk of gastrointestinal irritation.