Dosing of Megestrol Acetate for Malnutrition
The recommended dosage of megestrol acetate for treating malnutrition is 400-800 mg daily, with optimal efficacy typically seen in the 480-800 mg/day range. 1
Dosing Options and Formulations
Standard Formulation
- Regular oral suspension: 40 mg/mL concentration
- Recommended dose: 800 mg/day (20 mL daily) 2
Concentrated Formulation
- Megace ES (concentrated formula): 125 mg/mL concentration
- Recommended dose: 625 mg/day (5 mL or one teaspoon daily) 2
- More convenient dosing volume compared to standard formulation
Evidence-Based Recommendations
The ESPEN guidelines on nutrition in cancer patients provide high-level evidence supporting progestins (megestrol acetate) for appetite stimulation in malnourished patients. Multiple clinical trials and systematic reviews have demonstrated that megestrol acetate effectively increases appetite and body weight 1.
The NCCN Palliative Care guidelines specifically recommend megestrol acetate at 400-800 mg/day for patients with anorexia/cachexia with a life expectancy of months to years 1.
The ASCO guideline on management of cancer cachexia lists megestrol acetate at 200-600 mg/day as a pharmaceutical option, noting that the liquid formulation may be less expensive and more bioavailable than tablets 1.
Clinical Considerations
Benefits
- Improved appetite
- Weight gain (primarily fat mass, not lean body mass)
- Potential reduction in inflammatory markers in some patients 3, 4
Risks and Side Effects
- Edema
- Thromboembolic events (DVT, PE)
- Adrenal insufficiency
- Potential increased mortality in some populations 1
Special Populations
Dialysis patients:
- Lower doses (160 mg/day) have shown efficacy in improving appetite, serum albumin, and weight gain in peritoneal dialysis patients with minimal side effects 5
- Moderate doses (400 mg/day) have demonstrated improvements in nutritional parameters in maintenance dialysis patients 3
Children with malignancies:
- Has been used successfully to treat anorexia and weight loss in pediatric cancer patients, with increases in both fat mass and fat-free mass 6
Practical Dosing Algorithm
Initial dosing:
- Start with 400 mg/day for most patients
- Use 160 mg/day for frail patients or those with significant comorbidities
Dose titration:
- If inadequate response after 2-4 weeks, increase to 625-800 mg/day
- Maximum recommended dose: 800 mg/day
Duration of therapy:
- Typically 2-4 months
- Reassess nutritional status monthly
- Continue until target weight is achieved or side effects develop
Monitoring:
- Weight and appetite weekly
- Serum albumin monthly
- Monitor for edema, thromboembolism, and hyperglycemia
Important Caveats
- Megestrol acetate increases weight primarily through fat deposition rather than increasing lean body mass
- Risk of thromboembolic events requires careful patient selection and monitoring
- Consider discontinuing if significant side effects develop or if no improvement in appetite or weight after 4-8 weeks of therapy
- The concentrated formulation (Megace ES) provides equivalent efficacy with more convenient dosing (5 mL vs 20 mL)