What medications can stimulate appetite?

Medications to Stimulate Appetite

Progestins (megestrol acetate) are the most effective first-line medications for appetite stimulation, with corticosteroids as an alternative for short-term use in appropriate patients. 1

First-Line Options

Progestins

• Megestrol acetate:

  • Mechanism: Synthetic progestogen with appetite-stimulating properties
  • Dosing: 160-800 mg/day (optimal dose appears to be 160-480 mg/day) 1
  • Evidence: High-quality evidence shows significant increase in appetite and beneficial effect on body weight 1, 2
  • Best for: Cancer-related anorexia, AIDS-related wasting
  • Cautions: Potential side effects include thromboembolism, edema, impotence, vaginal spotting 1
  • Efficacy: Weight gain of approximately 2.25 kg compared to placebo 3

• Medroxyprogesterone acetate (MPA):

  • Dosing: Minimum effective dose 200 mg/day 1
  • Evidence: Significant increase in appetite, though effect on weight gain less established 1
  • Note: May be more available than megestrol acetate in some regions

Second-Line Options

Corticosteroids

• Prednisone, dexamethasone:
  • Mechanism: Anti-inflammatory effects that may reduce cytokine-mediated anorexia
  • Dosing: Short-term use (1-3 weeks) 1
  • Best for: Advanced cancer patients with limited life expectancy
  • Cautions: Significant side effects with prolonged use (muscle wasting, insulin resistance, infections) 1
  • Evidence: Good evidence for appetite stimulation (level B1) 1

Cannabinoids

• Dronabinol:
  • Mechanism: Synthetic THC that acts on cannabinoid receptors
  • Dosing: 2.5 mg 1-2 times daily (typically before meals) 4
  • Evidence: FDA-approved for AIDS-related anorexia, showed statistically significant improvement in appetite 4
  • Cautions: Neuropsychiatric side effects (feeling high, dizziness, confusion, somnolence) in approximately 18% of patients 4
  • Best for: AIDS-related anorexia, possibly cancer-related anorexia

Third-Line Options

Antidepressants

• Mirtazapine:
  • Dosing: 15-30 mg daily
  • Best for: Patients with concurrent depression and anorexia
  • Evidence: Limited but promising data in dementia patients (1.9 kg weight gain after 3 months) 1
  • Cautions: Sedation, dizziness

Patient-Specific Considerations

1. Cancer patients:

   • First choice: Megestrol acetate 160-480 mg/day
   • Alternative: Short-term corticosteroids (1-3 weeks)

2. AIDS patients:

   • First choice: Megestrol acetate 400-800 mg/day
   • Alternative: Dronabinol 2.5 mg 1-2 times daily

3. Elderly/dementia patients:

   • First choice: Consider mirtazapine if depression is present
   • Note: Guidelines specifically recommend against routine use of appetite stimulants in dementia 1

Monitoring and Precautions

• For all appetite stimulants:

  • Monitor weight regularly
  • Assess for fluid retention vs. true weight gain
  • Evaluate for adverse effects specific to the medication used

• Common pitfalls:

  1. Using appetite stimulants without addressing underlying causes of anorexia
  2. Prolonged use of corticosteroids leading to muscle wasting
  3. Failure to distinguish between increased fat mass vs. lean body mass
  4. Overlooking drug interactions, particularly with cannabinoids

Efficacy Considerations

• Medication effects are often modest and may primarily increase fat rather than lean body mass 5
• Consider combining pharmacologic therapy with nutritional support and, when appropriate, exercise programs 5
• Limited evidence for efficacy in the inpatient setting 6, 7

While these medications can help stimulate appetite, they should be part of a comprehensive approach that addresses underlying causes of anorexia when possible, with careful monitoring for adverse effects.