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# Megestrol Acetate
## Overview
Megestrol acetate is a synthetic progestin.
## Primary Indications
* **Cachexia, anorexia, or unexplained weight loss:** Associated with conditions such as acquired immunodeficiency syndrome (AIDS) or cancer.
* **Palliative treatment of advanced breast cancer:** Primarily in postmenopausal women.
* **Endometrial carcinoma:** Palliative treatment of recurrent or metastatic disease.
## Adult Dosing
* **Cachexia/Anorexia/Weight Loss:**
* Initial dose: 800 mg (20 mL) orally once daily.
* Some patients may respond to 400 mg (10 mL) orally once daily.
* Continue therapy as long as clinically indicated.
* **Breast Cancer:**
* 40 mg (10 mL) orally four times daily (400 mg daily).
* Alternatively, 160 mg (40 mL) orally once daily may be given.
* **Endometrial Carcinoma:**
* 40 mg (10 mL) orally four times daily (400 mg daily).
* Continue therapy as long as clinically indicated.
## Pediatric Dosing
There is no established pediatric dosing.
## Dose Adjustments
* **Renal Impairment:** No specific dose adjustment recommendations.
* **Hepatic Impairment:** No specific dose adjustment recommendations; use with caution.
## Contraindications
* Known or suspected pregnancy.
* Known hypersensitivity to megestrol acetate or any component of the formulation.
## Adverse Effects
* **Common:** Weight gain, increased appetite, hypertension, hot flashes, rash, dyspnea, nausea, diarrhea, abdominal pain, headache, edema.
* **Serious:** Thrombotic and thromboembolic events (e.g., deep vein thrombosis, pulmonary embolism), adrenal insufficiency (especially with abrupt discontinuation after prolonged use), hyperglycemia, new onset or exacerbation of diabetes mellitus, tumor flare.
## Key Drug Interactions
* **CYP3A4 Inhibitors/Inducers:** May alter megestrol acetate concentrations. Monitor for efficacy and toxicity.
* **Corticosteroids:** Concurrent use may increase the risk of adrenal insufficiency, especially with abrupt discontinuation of megestrol acetate.
## Monitoring
* Weight and appetite.
* Blood pressure.
* Signs and symptoms of thromboembolic events.
* Signs and symptoms of adrenal insufficiency (fatigue, weakness, dizziness, nausea, vomiting, hypotension).
* Blood glucose in patients with diabetes or at risk.
* Tumor response.
## Clinical Pearls
* May cause significant weight gain due to increased appetite.
* Abrupt discontinuation after prolonged therapy may lead to adrenal insufficiency. Taper dose if discontinuing.
* Use cautiously in patients with a history of thrombotic events.
* May mask symptoms of underlying malignancy.
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*Disclaimer: This information is intended for clinical use and does not substitute for professional medical judgment. Always verify current prescribing information and consult with a qualified healthcare provider for specific patient care decisions.*
