Megalia (Megestrol Acetate)

Megestrol acetate is used in clinical practice to address conditions related to weight loss and hormone‑responsive malignancies.

• Cachexia associated with AIDS or cancer: Improves appetite and promotes weight gain in affected patients.
• Hormone‑responsive breast cancer: Provides antineoplastic activity by modulating progesterone receptors.
• Other hormone‑responsive cancers: Used as part of therapy for certain prostate or endometrial cancers.

• Megestrol acetate is a synthetic progestogen that binds to intracellular progesterone receptors, altering gene transcription and exerting antineoplastic effects. The receptor activation also influences hypothalamic pathways that increase appetite, leading to weight gain in patients with disease‑related cachexia.

Megestrol acetate may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Edema: swelling of the lower extremities.
• Fatigue: generalized tiredness.
• Hot flashes: transient warmth and flushing.
• Mood changes: irritability or depression.
• Weight gain: therapeutic but may be excessive.

Serious or Rare Side Effects

• Thromboembolic events: deep‑vein thrombosis or pulmonary embolism.
• Adrenal insufficiency: reduced cortisol production.
• Hyperglycemia: elevated blood sugar levels, may worsen diabetes.
• Cushingoid syndrome: signs of excess glucocorticoid activity.
• Hepatotoxicity: liver enzyme elevations or hepatitis.
• Severe allergic reactions: rash, angioedema, or anaphylaxis.

Before initiating therapy, clinicians should evaluate patient‑specific risk factors and monitor for potential complications.

• Monitor blood glucose: hyperglycemia may develop, especially in diabetic patients.
• Assess thromboembolic risk: avoid in patients with active clotting disorders.
• Evaluate adrenal function: prolonged use can suppress the hypothalamic‑pituitary‑adrenal axis.
• Use caution in hepatic impairment: liver disease may increase drug exposure.
• Avoid in known hypersensitivity: discontinue if allergic reaction occurs.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Megestrol acetate can interact with several drug classes, requiring attention to avoid reduced efficacy or increased toxicity.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): markedly decrease plasma concentrations.
• Anticoagulants (e.g., warfarin): may enhance pro‑thrombotic risk.
• HIV protease inhibitors: can increase megastrol levels, raising toxicity risk.

Moderate Interactions (Monitor Closely)

• CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): may raise drug exposure.
• Antidiabetic agents (insulin, sulfonylureas): risk of hyperglycemia, dose adjustment may be needed.
• NSAIDs: combined use can increase gastrointestinal bleeding risk.