What is a good medication to stimulate appetite in an elderly patient with decreased appetite?

Appetite Stimulation in Elderly Patients

Mirtazapine 7.5 mg at bedtime is the preferred first-line medication for appetite stimulation in elderly patients with decreased appetite, particularly when concurrent depression may be present. 1, 2

Clinical Decision Algorithm

First-Line: Mirtazapine

• Start mirtazapine 7.5 mg at bedtime, with potential titration to 15-30 mg after 2-4 weeks if response is inadequate. 1, 2
• Mirtazapine offers dual benefit by treating underlying depression while simultaneously stimulating appetite and promoting weight gain. 1, 3
• One retrospective study demonstrated mean weight gain of 1.9 kg at 3 months and 2.1 kg at 6 months, with approximately 80% of patients experiencing some weight gain. 4, 1, 2
• The sedating properties make bedtime dosing ideal, and the medication is generally well-tolerated in elderly patients. 1
• Allow a minimum of 4-8 weeks for a full therapeutic trial before determining efficacy. 1

Critical Contraindication

• Do NOT use mirtazapine or any appetite stimulants in patients with dementia who lack concurrent depression, as evidence shows no consistent benefit and potentially harmful side effects outweigh uncertain benefits. 4, 1, 2

Second-Line: Megestrol Acetate

• If mirtazapine is ineffective or contraindicated, consider megestrol acetate 400-800 mg daily. 1, 2
• Approximately 1 in 4 patients will experience increased appetite and 1 in 12 will gain weight. 1
• The minimum effective dose is 160 mg/day, with no additional benefit above 480 mg/day. 2
• Serious safety concerns include thromboembolic events (reported in 2 patients in one trial), edema, adrenal suppression (cortisol suppression occurred in 33-78% of patients at doses of 200-800 mg), and higher mortality rates compared to placebo in some studies. 1, 5
• Megestrol acetate may attenuate benefits of resistance training, causing smaller gains or deterioration in muscle strength and functional performance. 4, 1
• Avoid in bed-bound patients due to deep vein thrombosis risk. 6
• Duration should not exceed 3 months. 6

Third-Line: Dexamethasone

• For patients with shorter life expectancy, dexamethasone 2-8 mg/day offers faster onset of action than other options. 1, 2
• Use with caution due to significant side effects with prolonged use. 1

Important Safety Considerations for Mirtazapine

Common Adverse Effects

• Somnolence occurs in 54% of patients (vs. 18% placebo) and leads to discontinuation in 10.4% of cases. 7
• Increased appetite occurs in 17% of patients (vs. 2% placebo). 7
• Weight gain ≥7% of body weight occurs in 7.5% of patients (vs. 0% placebo). 7
• Dry mouth affects 25% of patients (vs. 15% placebo). 7

Serious Warnings

• QT prolongation and Torsades de Pointes have been reported, particularly in overdose or patients with other risk factors. 7
• Serotonin syndrome risk when combined with MAOIs or other serotonergic drugs—concomitant use with MAOIs is contraindicated. 7
• Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) can occur and is sometimes fatal—discontinue immediately if suspected. 7
• Use with caution in patients where weight gain would be detrimental (obesity, cardiovascular disease, metabolic syndrome). 2

Monitoring Protocol

• Monitor weight and appetite weekly initially when starting mirtazapine. 2
• Regular reassessment is essential to evaluate benefit versus harm. 1, 2
• After 9 months of treatment, consider dosage reduction to reassess the need for continued medication. 1, 2
• Discontinue mirtazapine over 10-14 days to limit withdrawal symptoms. 1

Non-Pharmacological Adjuncts

• Encourage shared meals with family or other patients to improve intake through social interventions. 1, 2
• Offer smaller, more frequent meals with favorite foods and energy-dense options. 1, 2
• Consider fortified foods and oral nutritional supplements when dietary intake falls to 50-75% of usual intake. 1, 2
• Review and potentially discontinue medications that suppress appetite (such as iron supplements taken before meals). 1

Common Pitfalls to Avoid

• Do not use bupropion as it consistently promotes weight loss rather than gain. 3
• Avoid cannabinoids—multiple guidelines conclude insufficient evidence supports their routine use for appetite stimulation. 1
• Do not use flavor enhancers or odor stimulation routinely, as evidence shows no consistent benefit. 4
• Never combine mirtazapine with MAOIs due to serotonin syndrome risk. 7