Mirtazapine vs Trazodone

At full antidepressant doses, both mirtazapine and trazodone are effective for major depression. Mirtazapine has somewhat stronger evidence as a primary antidepressant, with clinical trials showing efficacy comparable to SSRIs and SNRIs. It may work slightly faster than SSRIs, with some improvement seen within the first 1-2 weeks.

Trazodone at full antidepressant doses (150-600 mg/day) is effective but is less commonly used as a primary antidepressant today due to sedation at higher doses. At low doses (25-100 mg), trazodone is one of the most commonly prescribed sleep aids in the United States, though this is an off-label use.

For patients with both depression and insomnia, mirtazapine may offer a single-medication solution, while trazodone at low doses is often added to another antidepressant specifically for sleep.

Mirtazapine's most notable side effect is increased appetite and weight gain, which can be significant (average 2-4 kg in clinical trials). This can be beneficial for patients with depression-related poor appetite and weight loss, but problematic for others. Sedation is common and dose-dependent (paradoxically, lower doses are more sedating). Dry mouth and elevated cholesterol can also occur.

Trazodone commonly causes sedation, dizziness, dry mouth, and headache. A rare but important side effect in males is priapism (prolonged painful erection), which requires immediate medical attention. Trazodone can also cause orthostatic hypotension (dizziness when standing), particularly in elderly patients.

Neither drug typically causes the sexual dysfunction commonly seen with SSRIs, which is an advantage for patients who have experienced this side effect with other antidepressants.

Both medications are available as affordable generics. Generic mirtazapine costs $5-$20 per month, and generic trazodone costs $4-$15 per month. Both are widely covered by insurance on preferred tiers.

Mirtazapine is taken once daily at bedtime, taking advantage of its sedating effect. The dose range for depression is 15-45 mg. It does not need to be taken with food and has few drug-food interactions.

Trazodone for sleep is typically taken at a low dose (25-100 mg) at bedtime. For depression, higher doses (150-600 mg) are divided throughout the day. It should be taken with food to reduce dizziness and improve absorption.

If you need treatment for both depression and insomnia, mirtazapine is a strong single-medication option that addresses both conditions. If you have poor appetite or unintended weight loss, mirtazapine's appetite-stimulating effect may be an added benefit.

If you primarily need a sleep aid to add to your existing antidepressant, low-dose trazodone is one of the most commonly used options. It avoids the weight gain associated with mirtazapine and has decades of safety data for this use.

If weight gain is a major concern, trazodone may be preferred. If you are male, be aware of the rare priapism risk with trazodone. Discuss your specific situation with your doctor to find the best fit.