Medications for Appetite Stimulation
Megestrol acetate is the most effective medication for stimulating appetite, with strong evidence supporting its use at doses of 160-800 mg/day. 1
First-Line Medications
Megestrol Acetate
- Efficacy: Significantly increases appetite and has beneficial effects on body weight in patients with cancer and other conditions 2, 1
- Dosing:
- Evidence quality: Level B1 (good quality evidence from randomized trials) 2
- Risks: Monitor for thromboembolic events (RR 1.84), edema (RR 1.36), and increased mortality risk (RR 1.42) 1, 4
Corticosteroids (e.g., Dexamethasone)
- Efficacy: Rapid appetite stimulation 2
- Best for: Patients with limited life expectancy (weeks to months) due to declining efficacy with long-term use 1
- Evidence quality: Level B1 2
- Risks: Muscle wasting, insulin resistance, infections 1
Mirtazapine
- Efficacy: Effective for appetite stimulation with additional benefits for sleep difficulties or mood disorders 1
- Dosing: 15-30 mg daily, typically at bedtime 1
- Particularly useful for: Patients with concomitant depression or anxiety
Second-Line Medications
Dronabinol (Synthetic THC)
- FDA approval: Approved for anorexia associated with weight loss in AIDS patients 5
- Efficacy: Statistically significant improvement in appetite, but less effective than megestrol acetate 2, 5
- Dosing: Initial dose 2.5 mg twice daily (before lunch and dinner) 5
- Side effects: Neuropsychiatric effects (feeling high, dizziness, confusion, somnolence) in approximately 18% of patients 5
- Caution: Risk of seizures in predisposed individuals; monitor patients with history of seizure disorders 5
Cyproheptadine
- Efficacy: May stimulate appetite but has reported adverse effects 2
- Evidence quality: Level C (weak methodology or inconsistent results) 2
Medications Without Proven Appetite-Stimulating Effects
The following medications should not be used for appetite stimulation 2, 1:
- Hydrazine sulfate (Level A evidence against use)
- Metoclopramide
- Nandrolone
- Pentoxifylline
- TNF inhibitors
- Insulin
Clinical Algorithm for Medication Selection
- Assess underlying cause of decreased appetite (e.g., cancer, AIDS, depression)
- Select first-line therapy based on patient condition:
- For cancer patients: Megestrol acetate (starting at 160 mg/day)
- For patients with depression: Mirtazapine (15-30 mg at bedtime)
- For end-of-life care: Corticosteroids (e.g., dexamethasone)
- Monitor effectiveness:
- Weigh patient weekly
- Reassess after 2-4 weeks
- If ineffective:
- Increase megestrol acetate dose (up to 480 mg/day)
- Or switch to alternative first-line agent
- Consider dronabinol as second-line option
- Monitor for side effects:
- For megestrol acetate: Thromboembolic events, edema, adrenal suppression
- For corticosteroids: Muscle wasting, insulin resistance, infections
- For dronabinol: Neuropsychiatric effects, potential seizures
Combination Approaches
For refractory cases, combination therapy may yield better outcomes than single agents:
- Megestrol acetate + L-carnitine + antioxidants has shown improved lean body mass, appetite, and quality of life compared to megestrol acetate alone 2
- Always combine pharmacological interventions with non-pharmacological approaches (small frequent meals, high-calorie foods, pleasant eating environment) 1
Important Caveats
- Discontinue ineffective treatments rather than continuing indefinitely 1
- For dronabinol, early morning administration appears associated with increased adverse effects; administer later in the day 5
- Thromboembolic risk with megestrol acetate is significant (1 in 6 patients) and should be carefully considered in patients with risk factors 2
- While cannabinoid-based interventions have shown efficacy for chemotherapy-induced nausea and AIDS-related anorexia, data for cancer-related anorexia-cachexia is limited 2