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# Megestrol Acetate
## Overview
Megestrol acetate is a synthetic progestational steroid. It is available in oral suspension and tablet formulations.
## Primary Indications
* Treatment of anorexia, cachexia, or unexplained significant weight loss in patients with acquired immunodeficiency syndrome (AIDS).
* Palliative treatment of advanced endometrial carcinoma and breast carcinoma.
## Adult Dosing
* **AIDS-related anorexia/cachexia:**
* Oral suspension: 625 mg (25 mL) once daily. Higher doses of 1250 mg (50 mL) daily have also been used.
* Tablets: 40 mg orally every 4 hours or 800 mg orally once daily.
* **Advanced endometrial carcinoma:** 40 mg orally 4 times daily.
* **Advanced breast carcinoma:** 160 mg orally once daily.
## Pediatric Dosing
There is no established pediatric dosing.
## Dose Adjustments
* **Renal Impairment:** No specific dose adjustments are recommended.
* **Hepatic Impairment:** No specific dose adjustments are recommended; however, caution is advised.
## Contraindications
* Known or suspected pregnancy.
* Undiagnosed vaginal bleeding.
* Known hypersensitivity to megestrol acetate.
* History of or active arterial or venous thromboembolic disease (e.g., deep vein thrombosis, pulmonary embolism, stroke, myocardial infarction).
## Adverse Effects
* **Common:** Weight gain, increased appetite, hot flashes, hypertension, edema, dyspnea, nausea, abdominal pain, diarrhea, rash, alopecia, vaginal bleeding, amenorrhea, sexual dysfunction.
* **Serious:** Thromboembolic events (pulmonary embolism, deep vein thrombosis, stroke, myocardial infarction), adrenal insufficiency, hyperglycemia, tumor flare.
## Key Drug Interactions
* **CYP3A4 Inducers (e.g., rifampin, phenytoin, carbamazepine):** May decrease megestrol acetate plasma concentrations, potentially reducing efficacy.
* **CYP3A4 Inhibitors (e.g., ketoconazole, itraconazole, ritonavir):** May increase megestrol acetate plasma concentrations.
* **Aminoglutethimide:** May decrease megestrol acetate plasma concentrations.
## Monitoring
* Blood pressure.
* Weight and appetite.
* Signs and symptoms of thromboembolic events.
* Blood glucose levels, especially in patients with diabetes or risk factors for diabetes.
* Adrenal function if prolonged use or withdrawal is suspected.
* Tumor response in patients with advanced cancer.
## Clinical Pearls
* Megestrol acetate is often used to stimulate appetite and promote weight gain in patients with severe wasting syndromes.
* The effectiveness and safety of doses higher than 800 mg daily for AIDS-related anorexia/cachexia are not well established.
* Thromboembolic events are a significant risk, particularly in patients with a history of such events or those who are immobile.
* Discontinuation of therapy may be necessary if serious adverse events occur.
* Oral suspension contains sugar, which may be a concern for diabetic patients.
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*Disclaimer: This information is intended for healthcare professionals. Always consult the most current prescribing information and relevant clinical guidelines before making any treatment decisions.*
