Which appetite stimulant is safer in a patient with pneumonia, history of Chronic Obstructive Pulmonary Disease (COPD), and malnutrition: Megace (megestrol acetate) or Marinol (dronabinol)?

Dronabinol (Marinol) is the Safer Choice for Appetite Stimulation in Patients with Pneumonia, COPD, and Malnutrition

Dronabinol (Marinol) is safer than megestrol acetate (Megace) for appetite stimulation in patients with pneumonia, COPD, and malnutrition due to fewer respiratory and thromboembolic risks.

Comparison of Safety Profiles

Megestrol Acetate (Megace)

• While effective for weight gain, megestrol acetate has significant concerns for COPD patients:
  • Increases risk of thromboembolic events (relative risk 1.84) 1
  • Causes fluid retention (relative risk 1.36) 1
  • May worsen respiratory status in pneumonia patients
  • Suppresses testosterone levels 2
  • Primarily increases fat mass rather than muscle mass 2, 3
  • Associated with increased mortality risk (relative risk 1.42) 1

Dronabinol (Marinol)

• Better safety profile for patients with respiratory conditions:
  • No significant risk of thromboembolic events
  • No fluid retention concerns
  • May provide additional benefits for COPD patients through bronchodilation
  • Does not suppress testosterone levels
  • Fewer contraindications in the setting of acute infection

Evidence for Efficacy

While megestrol acetate has been studied specifically in COPD patients 4, 3, showing weight gain of 2.3-3.2kg over 8 weeks, this weight gain is primarily fat mass rather than muscle mass, which is less beneficial for respiratory function.

Megestrol acetate does show some respiratory benefits:

• Decreased PaCO₂ (4.6 mmHg)
• Increased PaO₂ (2.8 mmHg) 3

However, these benefits must be weighed against the significant risks, especially in a patient with active pneumonia and COPD.

Clinical Decision Algorithm

1. Assess contraindications:

   • For a patient with pneumonia and COPD, avoid medications that increase fluid retention or thromboembolic risk
   • Megestrol acetate poses both these risks 1

2. Consider comorbidity impact:

   • Pneumonia: Requires careful fluid management; megestrol's fluid retention effect is problematic
   • COPD: Requires optimization of respiratory function; dronabinol has fewer respiratory side effects

3. Evaluate nutritional goals:

   • Both medications can stimulate appetite
   • For malnutrition in COPD, lean mass preservation is preferable to fat mass gain

4. Dosing considerations:

   • Start dronabinol at 2.5mg twice daily
   • Monitor for CNS side effects and adjust accordingly
   • Evaluate appetite improvement and weight gain after 2-4 weeks 1

Important Caveats and Monitoring

• For dronabinol:

  • Monitor for CNS effects (dizziness, confusion)
  • Start at low doses in elderly patients
  • May have additive effects with other CNS depressants

• Nutritional support:

  • Combine pharmacological intervention with non-pharmacological approaches
  • Provide small, frequent, nutrient-dense meals
  • Consider protein intake of 1.2-1.5 g/kg/day for patients with acute illness 1

• Follow-up monitoring:

  • Weight changes
  • Respiratory status
  • Appetite improvement
  • Side effects

Summary of Evidence Quality

The most recent and comprehensive evidence 1, 5 suggests that appetite stimulants have limited efficacy in the inpatient setting, but when necessary, the safety profile should guide selection. For patients with pneumonia, COPD, and malnutrition, dronabinol presents fewer risks related to respiratory function and thromboembolic events compared to megestrol acetate.