What medications can increase appetite in patients?

Medications to Increase Appetite

Megestrol acetate (400-800 mg/day) is the most effective appetite stimulant with evidence for weight gain, but should be monitored for side effects including thromboembolic events and fluid retention, and discontinued if ineffective after 4 weeks. 1

First-Line Medications

Megestrol Acetate

• Dosage: 400-800 mg/day (most effective dose range)
• Evidence: Strongest evidence for appetite stimulation and weight gain
• Mechanism: Progestational agent that stimulates appetite through unclear mechanisms
• Benefits:
  • Significant appetite improvement (95% of patients showed improvement after 2 weeks) 2
  • Weight gain (non-fluid)
  • Improved quality of life in cancer and AIDS patients
• Risks:
  • Thromboembolic events (relative risk 1.84)
  • Edema (relative risk 1.36)
  • Increased mortality risk (relative risk 1.42)
• Practical considerations:
  • Lower starting doses (80 mg twice daily) may be effective and reduce side effects 3
  • Dose-response effect exists for appetite stimulation 4

Mirtazapine

• Dosage: 15-30 mg daily
• Evidence: Demonstrated weight gain in patients with dementia (1.9 kg after three months) 5
• Benefits:
  • Additional benefits for sleep difficulties and mood disorders
  • Approximately 80% of dementia patients experience weight gain
• Risks:
  • FDA warnings include serotonin syndrome, QTc prolongation, and increased appetite/weight gain 6
  • Not recommended for weight loss without depression 5

Alternative Options

Cyproheptadine

• Dosage: 2-4 mg three times daily
• Evidence: Well-established safety profile in pediatric patients 1
• Best for: Pediatric patients requiring appetite stimulation

Dexamethasone

• Dosage: 2-8 mg/day
• Evidence: Provides rapid appetite stimulation 1
• Best for: Short-term use in patients with limited life expectancy
• Caution: Limit duration due to side effects (muscle wasting, insulin resistance)

Olanzapine

• Dosage: 5 mg/day
• Evidence: Alternative with fewer thromboembolic risks than megestrol acetate 1
• Caution: Monitor for metabolic side effects

Treatment Algorithm

1. Assess underlying cause of appetite loss (depression, cancer, AIDS, dementia, etc.)
2. Start with megestrol acetate 400 mg/day for most patients
   • For elderly or frail patients, consider starting at 160 mg/day
   • For patients with depression or sleep issues, consider mirtazapine 15-30 mg daily instead
3. Monitor after 2-4 weeks for:
   • Appetite improvement
   • Weight gain
   • Side effects (especially thromboembolic events)
4. Adjust treatment:
   • If effective with no significant side effects: continue
   • If ineffective: increase dose (up to 800 mg/day for megestrol acetate)
   • If side effects occur: reduce dose or switch medication

Important Considerations

• Combination with non-pharmacological approaches is essential:

  • Small, frequent meals (5-6 per day)
  • High-calorie, nutrient-dense foods
  • Pleasant eating environment
  • Moderate physical activity when possible

• Common pitfalls:

  • Failing to monitor for thromboembolic events with megestrol acetate
  • Not discontinuing ineffective medication after 4 weeks
  • Using high-dose steroids for prolonged periods
  • Overlooking non-pharmacological interventions

• Special populations:

  • Elderly: Start with lower doses and monitor closely for side effects
  • Cancer patients: Megestrol acetate shows particular benefit 2, 7
  • Dementia patients: Mirtazapine may be beneficial if depression is present 5

• Monitoring recommendations:

  • Regular weight measurements
  • Appetite assessment
  • Screening for edema and thromboembolic events
  • Quality of life assessment

Remember that while these medications can improve appetite and weight, they should be used as part of a comprehensive approach to nutrition and should be discontinued if ineffective after an adequate trial period.