What is the best starting dose of Remeron (mirtazapine) for appetite stimulation?

Best Starting Dose of Mirtazapine for Appetite Stimulation

The optimal starting dose of mirtazapine (Remeron) for appetite stimulation is 7.5 mg once daily at bedtime, as lower doses (7.5-15 mg) are more effective for promoting appetite due to stronger antihistaminic effects.

Pharmacological Basis for Low-Dose Effectiveness

Mirtazapine has a unique dose-response relationship that makes lower doses particularly effective for appetite stimulation:

• At lower doses (7.5-15 mg), mirtazapine has stronger antihistaminic effects, which are primarily responsible for its appetite-stimulating and sedating properties 1
• At higher doses (30-45 mg), the noradrenergic and serotonergic effects become more prominent, which are more relevant for antidepressant action but less important for appetite stimulation 2

Dosing Recommendations

Starting Dose

• Begin with 7.5 mg once daily at bedtime
• This can be achieved by cutting a 15 mg tablet in half or using a specialized compounded dose
• Administering at bedtime helps minimize daytime sedation

Dose Adjustment

• If inadequate response after 1-2 weeks, may increase to 15 mg once daily
• Doses higher than 15 mg are generally not recommended for appetite stimulation alone, as they:
  • Provide diminishing returns for appetite stimulation
  • Increase risk of side effects
  • Shift the pharmacological profile toward antidepressant effects rather than appetite stimulation

Evidence Supporting Low-Dose Approach

The American Family Physician guidelines specifically note that mirtazapine "promotes sleep, appetite, and weight gain" 3, with lower doses being more effective for these purposes. This is consistent with the unique pharmacodynamic profile of mirtazapine, where:

• Lower doses primarily block histamine H1 receptors, promoting appetite and sedation
• Higher doses increasingly block α2-adrenergic receptors and enhance serotonergic transmission 2, 4

Monitoring and Side Effects

Common side effects to monitor at this dose include:

• Sedation (most common)
• Increased appetite (desired effect)
• Weight gain
• Dry mouth

Special Considerations

1. Elderly patients: Consider starting at an even lower dose (3.75 mg) due to increased sensitivity to sedative effects

2. Patients with cardiovascular disease: Low-dose mirtazapine appears to be safe in patients with cardiovascular disease, as it has minimal cardiovascular effects 3, 2

3. Renal/hepatic impairment: Dose adjustment may be necessary as mirtazapine is extensively metabolized by the liver and excreted in urine 5, 6

Common Pitfalls to Avoid

1. Starting with too high a dose: The FDA-approved starting dose for depression is 15 mg 5, but for appetite stimulation alone, starting with 7.5 mg minimizes sedation while still providing appetite benefits

2. Expecting immediate results: While appetite stimulation may begin within days, allow 1-2 weeks for full effect

3. Missing the paradoxical effect: Unlike most medications, higher doses of mirtazapine (>15 mg) may actually be LESS effective for appetite stimulation than lower doses due to the shifting receptor profile at higher doses 1, 2

By starting with a low dose of 7.5 mg at bedtime, you maximize the appetite-stimulating effects while minimizing potential side effects, particularly excessive sedation.