Appetite Stimulants for a 20-Year-Old
For a 20-year-old with decreased appetite, megestrol acetate (400-800 mg/day) is the most effective first-line pharmacological option, improving appetite in approximately 25% of patients and producing modest weight gain in about 8% of patients. 1
Clinical Context Assessment Required
Before initiating pharmacological appetite stimulation, determine the underlying cause:
If Depression is Present
- Mirtazapine (7.5-30 mg at bedtime) is the optimal choice when depression coexists with appetite loss, addressing both conditions simultaneously 1, 2
- In patients with dementia and depression, mirtazapine at 30 mg daily produced mean weight gain of 1.9 kg at three months and 2.1 kg at six months, with 80% experiencing weight gain 3
- Avoid bupropion, as it is the only antidepressant consistently shown to promote weight loss 2
If Nausea/Vomiting is Present
- Olanzapine (5 mg/day) should be considered when concurrent nausea or vomiting complicates appetite loss 1, 4
If Rapid Effect is Needed
- Dexamethasone (2-8 mg/day) offers faster onset of action compared to megestrol acetate and may also help with fatigue 1, 4
- However, prolonged use causes significant side effects including hyperglycemia, muscle wasting, and immunosuppression 1
Pharmacological Options Ranked by Evidence
First-Line: Megestrol Acetate
- Dose: 400-800 mg/day 1
- Evidence from 30 RCTs demonstrates effectiveness for appetite and weight 3
- Superior to placebo, dronabinol, and fluoxymestrone for appetite stimulation 3
- Critical caveat: Can cause fluid retention and increased risk of thromboembolic events 1
Second-Line: Cannabinoids (Dronabinol)
- Limited evidence but may increase meal consumption in certain populations 1, 4
- A Cochrane review of cystic fibrosis patients showed appetite stimulants (including cannabinoids) may increase weight at three months (MD 1.25 kg) and six months (MD 3.80 kg) 5
- Inpatient studies show numerical improvements in meal intake (mean change 17.12%) but no significant difference between agents 6
Alternative: Cyproheptadine Hydrochloride
- Long-term trial in cystic fibrosis showed significant weight gain with acceptable side-effect profile over 9 months 7
- Dose: 4 mg up to four times daily 7
- Maintains effect over time with mild side effects 7
Non-Pharmacological Approaches to Implement Concurrently
These strategies should be implemented alongside any pharmacological intervention:
- Provide oral nutritional supplements when food intake is 50-75% of usual intake 1
- Serve energy-dense meals to meet nutritional requirements without increasing meal volume 1, 2
- Offer protein-enriched foods and drinks to improve protein intake 1, 2
- Make snacks available between meals 1
- Provide emotional support during meals 2, 4
Critical Monitoring Requirements
For a 20-year-old, standard adult dosing applies, but regular reassessment is essential:
- Monitor for thromboembolic events with megestrol acetate 1
- Assess for hyperglycemia, muscle wasting, and immunosuppression with dexamethasone 1
- Evaluate benefit versus harm regularly, as appetite stimulants have limited efficacy in some populations 8
- Recent systematic review found these medications have limited efficacy on improving appetite and meal intake in hospitalized adults, with no significant weight change 8
Important Contraindications
Do NOT use appetite stimulants if:
- The patient has dementia (drugs to stimulate appetite should NOT be used in persons with dementia due to limited evidence and potential risks) 3, 4
- The patient is on warfarin without careful INR monitoring, as megestrol acetate and other agents can significantly increase INR 9
Treatment Duration
- Typical course is 2-4 weeks, which may be repeated intermittently as indicated 9
- Long-term use (up to 9 months) has been studied with cyproheptadine showing maintained effectiveness 7
- Benefits must be weighed against risks, particularly with prolonged corticosteroid use (effects on appetite last only a few weeks in some studies) 3