What is the best appetite stimulant for an elderly patient with decreased appetite?

Appetite Stimulation in the Elderly

Primary Recommendation

For elderly patients with decreased appetite, mirtazapine 7.5 mg at bedtime is the first-line pharmacological option when concurrent depression is present or suspected, while megestrol acetate 400-800 mg daily can be considered for patients without depression, though both should only be used after addressing reversible causes and attempting non-pharmacological interventions. 1

Critical Initial Assessment

Before any pharmacological intervention, you must:

• Screen for depression specifically - this determines your entire treatment pathway, as mirtazapine is only appropriate when depression coexists with appetite loss 1, 2
• Identify and discontinue appetite-suppressing medications - particularly iron supplements and medications taken before meals that may be non-essential 1
• Evaluate for treatable medical causes - including poor dentition (refer to dentist), swallowing difficulties (refer to speech therapy), and malnutrition using validated tools (NRS-2002, MNA, or MUST) 1

Pharmacological Treatment Algorithm

If Depression is Present or Suspected:

Mirtazapine is your only appropriate choice 1, 2, 3:

• Start at 7.5 mg at bedtime - the sedating properties make bedtime dosing ideal 1
• Maximum dose is 30 mg at bedtime 1, 3
• Allow 4-8 weeks for full therapeutic trial before assessing efficacy 1, 3
• Expected outcomes: 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 1, 3
• Monitor for: Somnolence (54% of patients), QTc prolongation in high-risk patients, serotonin syndrome if combined with other serotonergic drugs, and angle-closure glaucoma in susceptible patients 4

If Depression is Absent:

Megestrol acetate 400-800 mg daily is your option, though with significant caveats 1:

• Approximately 1 in 4 patients will have increased appetite and 1 in 12 will gain weight - modest benefit-to-harm ratio 1
• Critical safety concerns include thromboembolic events (occurred in 2 patients in one trial), adrenal suppression (33-78% had morning cortisol <8 ng/mL at various doses), edema, impotence, and vaginal spotting 1, 5, 6
• Functional impairment risk: In older hospitalized patients with functional decline, megestrol acetate actually attenuated benefits of resistance training, causing smaller gains or deterioration in muscle strength compared to placebo 1, 2
• One Cochrane review found higher rates of deaths in the megestrol acetate group compared to placebo 1
• Prealbumin increases occur in dose-response fashion (400 mg and 800 mg groups showed significant improvement at 20 days), but this doesn't necessarily translate to clinical benefit 5

Special Population: Dementia Patients

Do NOT use appetite stimulants in dementia patients unless concurrent depression is documented 1, 2, 3:

• 89% consensus agreement among clinical nutrition guidelines that appetite stimulants should not be used in dementia due to very limited evidence, inconsistent effects, and potentially harmful side effects that outweigh uncertain benefits 2
• The only exception: Mirtazapine may be used if the dementia patient has concurrent depression requiring treatment, as it addresses both conditions simultaneously 2, 3
• Three small placebo-controlled trials found no significant effect of cannabinoids on body weight, BMI, or energy intake in dementia patients 1, 3

Non-Pharmacological Interventions (Prioritize These First)

Social interventions 1, 2:

• Encourage shared meals with family or place patients at dining tables with others - this significantly improves intake and quality of life

Dietary modifications 1, 2:

• Offer smaller, more frequent meals with favorite foods
• Provide energy-dense options and fortified foods/oral nutritional supplements when dietary intake falls to 50-75% of usual intake (Grade B recommendation with 97% consensus)

Oral care and dental treatment 2:

• Maintain oral functions to prevent pneumonia and other complications

Monitoring Protocol

Regular reassessment schedule 1, 3:

• Evaluate at weeks 1,2,4,8, and 12 to assess benefit versus harm
• After 9 months of mirtazapine treatment, consider dosage reduction to reassess need for continued medication 1
• Discontinue mirtazapine over 10-14 days to limit withdrawal symptoms 1

For megestrol acetate 5, 6:

• Monitor for signs of adrenal insufficiency (hypotension, weakness, fatigue)
• Consider cosyntropin stimulation test if adrenal insufficiency is suspected
• Monitor for thromboembolic events

Critical Pitfalls to Avoid

• Never use appetite stimulants as first-line without addressing reversible causes - medication review and non-pharmacological interventions must come first 1
• Never use megestrol acetate or other appetite stimulants in dementia patients without depression - the evidence shows no benefit and potential harm 2, 3
• Never combine mirtazapine with MAOIs - discontinue mirtazapine before initiating MAOI treatment 4
• Never ignore the functional impairment risk with megestrol acetate - it can actually worsen muscle strength and functional performance, particularly problematic in frail elderly 1, 2
• For end-of-life patients, focus on comfort and quality of life rather than nutritional goals - overly aggressive interventions can increase suffering 1