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

Medications for Appetite Stimulation in Anorexia

For cancer-related anorexia, megestrol acetate (400-800 mg/day) is the most effective first-line pharmacological appetite stimulant, with approximately 25% of patients experiencing improved appetite and 8% achieving modest weight gain. 1, 2

Context-Specific Recommendations

For Cancer-Related Anorexia

First-line pharmacological options:

• Megestrol acetate at 160-480 mg/day is the optimal dose range, with 160 mg/day being the minimum effective dose 3
• Doses above 480 mg/day show no additional efficacy 3
• Critical warning: Risk of thromboembolic events occurs in 1 in 6 patients, with mortality risk in 1 in 23 patients 2
• Fluid retention is a common adverse effect 2

Alternative options when megestrol acetate fails or is contraindicated:

• Corticosteroids (dexamethasone 2-8 mg/day) provide rapid onset of appetite stimulation but should be restricted to 1-3 weeks due to serious adverse effects including muscle wasting, insulin resistance, and infections 3, 1

• Best suited for patients with shorter life expectancy who may also benefit from symptom relief of pain or nausea 3

• The antianorectic effect is transient and disappears after a few weeks 3

• Medroxyprogesterone acetate (MPA) at minimum 200 mg/day increases appetite significantly, though weight gain effects are less consistent than megestrol acetate 3

For Anorexia with Concurrent Depression

• Mirtazapine 7.5-30 mg at bedtime is the ideal choice for patients with both depression and appetite loss 1, 4
• In one retrospective study, 30 mg daily resulted in mean weight gain of 1.9 kg at three months and 2.1 kg at six months, with 80% of patients experiencing weight gain 3, 4
• FDA-labeled adverse effects include: increased appetite (17% vs 2% placebo), weight gain (12% vs 2% placebo), and somnolence (54% vs 18% placebo) 5

For Anorexia with Concurrent Nausea/Vomiting

• Olanzapine 5 mg/day may be particularly beneficial for patients with nausea, vomiting, or anxiety 1, 2
• Randomized trials demonstrate effectiveness in cancer-related anorexia 2

For Patients with Dementia

• Appetite stimulants should NOT be used in persons with dementia due to insufficient evidence of benefit and potential for harmful side effects 3
• Focus instead on non-pharmacological approaches: feeding assistance, emotional support during meals, increased nursing time for feeding, and behavioral/communication strategies 3, 1

Third-Line Options

Cannabinoids (dronabinol 2.5-7.5 mg every 4 hours as needed):

• Limited evidence compared to megestrol acetate 2
• May benefit select patients with chemosensory alterations 2
• Caution: Risk of delirium in elderly patients; subject to local regulations 2
• Dronabinol, metoclopramide, nandrolone, and pentoxifylline have NOT been shown to have appetite-stimulating effects in rigorous trials 3

Medications to Avoid

• Cyproheptadine may have modest benefit but adverse effects limit its use 3
• Hydrazine sulphate is NOT an appetite stimulant 3
• Bupropion is contraindicated as it consistently promotes weight loss 4

Important Clinical Caveats

Timing of pharmacological intervention:

• Appetite stimulants should be used in combination with or after failure of dietetic and oral nutritional management 3
• Provide oral nutritional supplements when food intake is 50-75% of usual intake 1

Monitoring requirements:

• Regular reassessment is essential to evaluate benefit versus harm 1
• Lower starting doses should be used for elderly patients with close monitoring for sedation and thromboembolic events 1, 4
• Address reversible causes of anorexia first: oropharyngeal candidiasis, depression, pain, constipation, and nausea 2

For psychiatric anorexia nervosa specifically:

• No medications are FDA-approved for treatment of anorexia nervosa 6
• Antidepressants should not be used as sole therapy 7
• SSRIs (particularly fluoxetine) may aid in relapse prevention in weight-restored patients but lack efficacy during acute treatment 7, 8
• Second-generation antipsychotics, particularly olanzapine, show some benefit for weight gain but are not advised as stand-alone treatment 8, 9