What medications can be used to increase appetite in patients with decreased appetite?

Medications for Increasing Appetite

Progestins (megestrol acetate) are the most effective first-line pharmacological option for increasing appetite in patients with decreased appetite, particularly in cancer and AIDS patients. 1, 2

First-Line Options

Progestins

• Megestrol acetate:

  • Most extensively studied appetite stimulant with high-quality evidence 1, 3
  • Dosing: 160-800 mg/day (optimal dose appears to be 160-480 mg/day) 1
  • Benefits:
    • Significantly increases appetite (level of evidence: B1) 1
    • Produces weight gain in cancer and AIDS patients 4, 3
    • Reduces nausea and vomiting in some patients 4
  • Risks:
    • Thromboembolic events (RR 1.84) 2, 3
    • Edema (RR 1.36) 2, 3
    • Increased mortality risk (RR 1.42) 2, 3
    • Impotence and vaginal spotting 1

• Medroxyprogesterone acetate (MPA):

  • Alternative progestin with appetite-stimulating effects 1
  • Dosing: Minimum effective dose is 200 mg/day 1
  • Benefits: Significant increase in appetite (level of evidence: B1) 1
  • Note: Effect on weight gain is less established than megestrol acetate 1

Second-Line Options

Corticosteroids

• Dexamethasone:
  • Dosing: 2-8 mg/day 2
  • Benefits:
    • Rapid onset of action
    • Comparable efficacy to megestrol acetate for appetite stimulation 2
  • Risks:
    • Limited duration of effect
    • Myopathy
    • Hyperglycemia
    • Immunosuppression
    • Best used for short-term (1-3 weeks) appetite stimulation 1

Cannabinoids

• Dronabinol (THC):
  • FDA-approved for treatment of anorexia in AIDS patients 5
  • Dosing:
    • For AIDS-related anorexia: 2.5 mg twice daily (1 hour before lunch and dinner) 5
    • For elderly: May reduce to once daily (1 hour before dinner or bedtime) 5
  • Benefits:
    • May improve chemosensory perception and pre-meal appetite 1
    • Can help with nausea and vomiting 5
  • Risks:
    • Neuropsychiatric effects (dizziness, euphoria, paranoid reactions, somnolence) 5
    • Cardiovascular effects (tachycardia, hypotension) 5
    • Seizures in predisposed patients 5
    • Controlled substance (CIII) with potential for abuse 5

Atypical Antipsychotics

• Olanzapine:
  • Dosing: 5 mg/day 2
  • Benefits:
    • Appetite stimulation
    • Additional benefit for nausea control
    • Particularly useful when depression contributes to anorexia 2

Antidepressants

• Mirtazapine:
  • Consider when depression contributes to decreased appetite 2, 6
  • Particularly useful in patients with dementia and depression 2
  • Showed numerical improvement in meal intake in hospitalized patients 6

Special Considerations

Inpatient Setting

• Dronabinol, megestrol, and mirtazapine all showed numerical improvements in meal intake when initiated in hospitalized patients 6
• No significant differences between these agents in terms of meal intake improvement or weight gain in the inpatient setting 6

Patient-Specific Factors

• Cancer patients: Progestins (megestrol acetate) have the strongest evidence 1, 4
• AIDS patients: Megestrol acetate or dronabinol are FDA-approved options 5, 3
• Elderly patients: Consider lower doses and monitor for side effects, particularly with dronabinol 5
• Patients with depression: Consider mirtazapine 2

Common Pitfalls to Avoid

1. Failing to address reversible causes of appetite loss before starting pharmacotherapy (pain, constipation, nausea/vomiting, depression) 2
2. Not considering potential drug interactions, especially with CNS depressants and cardiovascular medications 5
3. Continuing ineffective treatments beyond 4 weeks without reassessment 2
4. Using appetite stimulants indiscriminately without weighing risks and benefits 2
5. Not monitoring for serious adverse effects such as thromboembolic events with megestrol acetate 2, 3

Monitoring Recommendations

• Assess appetite improvement and weight gain within 2-4 weeks of starting therapy 2
• Monitor for specific adverse effects based on medication choice:
  • Progestins: Thromboembolic events, edema
  • Corticosteroids: Hyperglycemia, muscle weakness
  • Dronabinol: Neuropsychiatric effects, changes in blood pressure
  • Olanzapine: Metabolic effects, sedation
• Discontinue if no benefit is observed after an adequate trial or if adverse effects outweigh benefits