What medications can be used to stimulate appetite in patients with poor appetite?

Medications for Poor Appetite

Megestrol acetate is the most effective medication for appetite stimulation, with dosages of 400-800mg daily showing positive effects on appetite and weight gain in clinical studies. 1

First-Line Pharmacological Options

Megestrol Acetate

• Strongest evidence for appetite stimulation in cancer patients and those with weight loss
• Dosage: 400-800mg daily
• Mechanism: Progestational agent
• Efficacy: Demonstrated positive effects on appetite and body weight in RCTs 1
• Monitoring:
  • Screen for thromboembolic risk factors before initiating
  • Monitor for thromboembolic events (RR 1.84), edema, blood glucose levels
  • Assess effectiveness after 2-4 weeks; discontinue if no improvement

Dronabinol (Marinol)

• FDA-approved for appetite stimulation in AIDS-related anorexia
• Dosage: Initial 2.5mg before lunch and dinner (5mg/day total)
  • May reduce to 2.5mg once daily at supper or bedtime if side effects occur
• Mechanism: Cannabinoid receptor agonist
• Efficacy: Statistically significant improvement in appetite in AIDS patients 2
• Side effects: Feeling high, dizziness, confusion, somnolence (occurred in 18% of patients)

Mirtazapine

• Antidepressant with appetite-stimulating properties
• Dosage: 15-30mg daily (typically at bedtime)
• Mechanism: Noradrenergic and specific serotonergic antidepressant
• Efficacy: One small retrospective study showed mean weight gain of 1.9kg after three months and 2.1kg after six months in dementia patients 3
• Best for: Patients with concurrent depression and appetite loss

Cyproheptadine

• Antihistamine with appetite-stimulating properties
• Efficacy: Randomized, double-blind, placebo-controlled study showed statistically significant appetite improvement compared to placebo 4
• Side effects: Primarily somnolence
• Well-tolerated in clinical trials

Second-Line Options

Olanzapine

• Atypical antipsychotic with appetite-stimulating properties
• Consider for patients with concurrent psychosis or severe agitation
• Side effects: Metabolic syndrome, weight gain, sedation

Patient Selection Considerations

1. For patients with depression and appetite loss:

   • Mirtazapine is preferred (addresses both conditions) 1

2. For cancer patients with cachexia:

   • Megestrol acetate is first-line (strongest evidence) 1

3. For AIDS patients with anorexia:

   • Dronabinol is FDA-approved specifically for this indication 2

4. For elderly patients:

   • Start with lower doses and monitor closely
   • Mirtazapine may be beneficial in dementia patients with concurrent depression 3
   • Avoid appetite stimulants in dementia without depression (insufficient evidence) 3

Monitoring and Assessment

• Assess effectiveness after 2-4 weeks of therapy
• Discontinue if no improvement in appetite or weight
• For megestrol acetate: monitor for thromboembolic events, edema, hyperglycemia
• For dronabinol: monitor for neuropsychiatric effects, especially in elderly or those with psychiatric history 2

Important Caveats

• Evidence for appetite stimulants in the inpatient setting is limited 5, 6
• Most studies show numerical improvements in meal intake but may not reach statistical significance in hospitalized patients
• Abrupt discontinuation of mirtazapine can lead to discontinuation syndrome (anxiety, nausea, tremor, appetite loss) - taper when discontinuing 7
• Current guidelines do not recommend appetite stimulants for dementia patients without depression 3

Non-Pharmacological Approaches

While medications can help, always consider complementing with:

• Small, frequent meals
• High-calorie snacks
• Food preferences
• Liberalizing dietary restrictions
• Treating underlying conditions causing appetite loss

Remember that medication should not be used alone but in combination with an intensive lifestyle program for optimal results 3.