What are the recommended starting and target doses of trazodone for insomnia and for major depressive disorder in adults, and how should dosing be adjusted for elderly patients or those with hepatic impairment?

Trazodone Dosing Recommendations

For major depressive disorder, start trazodone at 150 mg/day in divided doses (or predominantly at bedtime), increasing by 50 mg every 3-4 days as tolerated, with target doses of 150-300 mg/day for outpatients and up to 600 mg/day for severely depressed inpatients; for insomnia secondary to depression, use 50-100 mg as a single dose at bedtime, though note that trazodone is NOT recommended as a standalone treatment for primary insomnia. 1, 2

Major Depressive Disorder Dosing

Starting Dose

• Initial: 150 mg/day in divided doses 1
• Begin at low dose and titrate gradually based on clinical response and tolerability
• Drowsiness may necessitate giving the majority of the daily dose at bedtime 1

Titration Schedule

• Increase by 50 mg/day every 3-4 days 1
• Monitor for clinical response and adverse effects during titration

Target Doses

• Outpatients: 150-300 mg/day (maximum 400 mg/day in divided doses) 1, 3
• Inpatients (severe depression): up to 600 mg/day in divided doses 1
• Single nighttime dosing at 150 mg, increased to 200-300 mg as needed, is equally effective as divided dosing and reduces daytime drowsiness 4

Administration

• Take shortly after a meal or light snack 1
• Can be swallowed whole or broken along score line 1
• Dosing predominantly at bedtime is favored due to the 3-9 hour half-life and improved tolerability 4

Insomnia Secondary to Depression

Use 50-100 mg as a single dose before bedtime 5, 6

• The 100 mg dose shows superior efficacy for sleep improvement 5
• This is for insomnia accompanying depression, not primary insomnia

Critical Caveat: Primary Insomnia

The American Academy of Sleep Medicine (2017) recommends AGAINST using trazodone for primary insomnia (sleep onset or maintenance insomnia without depression), based on trials of 50 mg doses showing insufficient evidence of benefit 2. This is a weak recommendation with very low quality evidence, but it represents the most recent guideline position.

Special Populations

Elderly Patients

• Start at 150 mg/day total (can be given as 50 mg three times daily initially) 7
• This higher starting dose (compared to historical 25 mg TID) was better tolerated and more effective in elderly inpatients 7
• Geriatric patients respond similarly to younger adults with single nighttime dosing 4
• Monitor for orthostatic hypotension, which occurs more frequently in older adults 3
• Trazodone is considered a preferred agent for elderly patients with depression 8

Hepatic Impairment

• The FDA label does not provide specific dose adjustments for hepatic impairment 1
• Use clinical judgment: start low, titrate slowly, monitor closely for adverse effects
• Consider that trazodone is hepatically metabolized via CYP3A4

Drug Interactions Requiring Dose Adjustment

Strong CYP3A4 Inhibitors

• Consider dose reduction based on tolerability when co-administered with strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) 1

Strong CYP3A4 Inducers

• Consider dose increase based on therapeutic response when co-administered with strong CYP3A4 inducers (e.g., carbamazepine, rifampin) 1

MAOIs

• Wait at least 14 days between discontinuing an MAOI and starting trazodone, or vice versa 1

Discontinuation

Taper gradually rather than stopping abruptly to minimize withdrawal symptoms 1. The specific taper schedule is not defined in the FDA label, but gradual dose reduction over weeks is standard practice.

Key Advantages Supporting These Doses

• Low sexual dysfunction risk compared to SSRIs 3, 9
• Weight-neutral effects 3, 9
• Effective for insomnia, anxiety, and psychomotor agitation accompanying depression 3, 9
• Rapid onset of action 3
• Low anticholinergic activity 9

Common Pitfalls to Avoid

1. Don't use trazodone monotherapy for primary insomnia - guideline evidence does not support this 2
2. Don't underdose for depression - full antidepressant effect requires 150-300 mg/day, not the 25-75 mg used for sedation 10
3. Don't forget cardiovascular monitoring - rare but serious risks include QT prolongation, orthostatic hypotension, and cardiac arrhythmias, especially in elderly or those with cardiovascular disease 3
4. Screen for bipolar disorder before initiating - as with all antidepressants 1
5. Warn about priapism - rare but requires immediate medical attention 3

Most Common Adverse Effects

Somnolence, headache, dizziness, dry mouth, blurred vision, nausea 3, 11. These are dose-dependent and often improve with continued use or dose adjustment.