What is the recommended dosage and usage of Trazodone (antidepressant) for treating major depressive disorder and insomnia?

Trazodone Dosage for Major Depressive Disorder and Insomnia

For major depressive disorder, trazodone should be initiated at 150 mg/day in divided doses and may be increased gradually to a maximum of 400 mg/day for outpatients or 600 mg/day for inpatients. 1

Dosing Regimen for Major Depressive Disorder

Initial Dosing and Titration

• Start with 150 mg/day in divided doses 1
• Increase by 50 mg/day every 3-4 days based on clinical response and tolerance 1
• Maximum dose:
  • Outpatients: 400 mg/day in divided doses
  • Inpatients (more severely depressed): up to 600 mg/day in divided doses 1

Administration Recommendations

• Take shortly after a meal or light snack to improve tolerance 1
• Can be swallowed whole or administered as a half tablet by breaking along the score line 1
• Once an adequate response is achieved, dosage may be gradually reduced with subsequent adjustments based on therapeutic response 1

Single Daily Dosing Option

• Research supports a single nighttime dose regimen (primarily at bedtime) 2
• Studies comparing multiple daytime dosing to single bedtime dosing have shown equal efficacy in relieving depression 2
• Single nighttime dosing is more effective for improving sleep with less daytime drowsiness, especially at treatment initiation 2

Dosing for Insomnia in Depression

• When trazodone is specifically targeted for depression with insomnia, the effective antidepressant dose range is typically 150-300 mg/day 3, 4
• Lower doses are often used when trazodone is prescribed to augment another antidepressant's effect, particularly for addressing insomnia 4
• Trazodone is particularly effective for patients with major depression and comorbid insomnia 5

Special Considerations

Drug Interactions

• When coadministered with strong CYP3A4 inhibitors: Consider reducing trazodone dose based on tolerability 1
• When coadministered with strong CYP3A4 inducers: Consider increasing trazodone dose based on therapeutic response 1
• At least 14 days must elapse between discontinuation of an MAOI antidepressant and initiation of trazodone 1

Discontinuation

• Gradually reduce the dosage rather than stopping abruptly to avoid discontinuation symptoms 1

Safety Monitoring

• Screen patients for bipolar disorder prior to starting trazodone 1
• Monitor for common side effects:
  • Somnolence, headache, dizziness, and dry mouth 3
  • Orthostatic hypotension (especially in cardiovascular disease patients or older adults) 3
  • QT interval prolongation and cardiac arrhythmias (rare) 3
  • Priapism (rare but serious) 3

Advantages for Specific Populations

• Low anticholinergic activity 3, 4
• Low risk of weight gain and sexual dysfunction compared to SSRIs 3, 4
• Effective for depression with anxiety and psychomotor agitation 4
• Beneficial for elderly patients (though lower doses may be needed) 6

Practical Dosing Algorithm

1. For MDD with insomnia:

   • Start with 150 mg/day, with the majority of the dose at bedtime
   • Titrate by 50 mg every 3-4 days as needed
   • Target dose: 150-300 mg/day for full antidepressant efficacy 3, 2

2. For primarily insomnia in patients on other antidepressants:

   • Use lower doses than the full antidepressant dosage 4

3. For elderly patients:

   • Start with lower doses and titrate more cautiously 6