What is the maximum daily dose of trazodone for an elderly patient (≥65 years)?

Maximum Daily Trazodone Dose in Elderly Patients

For elderly patients (≥65 years), the maximum daily dose of trazodone should not exceed 300-400 mg/day, with most patients responding adequately to lower doses of 150-300 mg/day. 1

Evidence-Based Dosing Recommendations

Standard Maximum Dose

• Maximum tolerated doses in elderly patients are 300-400 mg/day, which is lower than the 600 mg/day tolerated by younger patients 1
• The outpatient maximum should not exceed 400 mg/day in divided doses; hospitalized patients may receive up to 600 mg/day only with active monitoring for side effects 2

Optimal Starting and Maintenance Dosing

• Trazodone is best initiated at 150 mg given predominantly at bedtime, then increased as needed to 200-300 mg for full antidepressant efficacy 3
• Elderly patients respond similarly to single nighttime dosing as younger patients, with equal efficacy compared to multiple daily dosing 3
• A study in elderly inpatients demonstrated that starting at 150 mg total daily dose (50 mg three times daily) was well tolerated and more rapidly effective than lower starting doses 4

Age-Related Pharmacokinetic Changes

Altered Drug Metabolism in Elderly

• Elderly men show significantly reduced trazodone clearance (1.65 vs. 2.31 ml/min/kg) and increased elimination half-life (8.2 vs. 4.7 hours) compared to young men 5
• Elderly women demonstrate increased volume of distribution (1.5 vs. 1.27 L/kg) and prolonged half-life (7.6 vs. 5.9 hours) 5
• These pharmacokinetic changes indicate a need for dosage reduction during chronic therapy in elderly patients 5

Special Considerations

Obesity Impact on Dosing

• In obese elderly patients, dosage should be based on ideal body weight rather than total body weight, as obesity greatly increases volume of distribution and prolongs half-life (13.3 vs. 5.9 hours) 5

Safety Profile in Elderly

• Trazodone demonstrates notably lower incidences of anticholinergic and cardiovascular effects compared to older tricyclic antidepressants in elderly patients 1
• However, orthostatic hypotension, arrhythmias, and priapism require close monitoring 1
• Drowsiness is the most common adverse effect, followed by dizziness, dry mouth, and nervousness 2

Clinical Pitfalls to Avoid

Common Dosing Errors

• Do not exceed 400 mg/day in outpatient elderly patients, as higher doses increase risk of adverse effects without proportional benefit 1, 2
• Avoid rapid dose escalation; allow 1-2 weeks between dose adjustments due to the prolonged half-life in elderly patients 5
• Do not use total body weight for dosing calculations in obese elderly patients 5

Drug Interactions

• When combining trazodone with other serotonergic agents (SSRIs, other antidepressants), monitor for serotonin syndrome and consider lower maximum doses 6
• Monitor for QT prolongation when trazodone is combined with medications like citalopram, especially at doses >40 mg/day 6

Timeline for Therapeutic Response

• One-third of inpatients and one-half of outpatients show significant therapeutic response by the end of the first week, with remaining patients responding within 2-4 weeks 2
• Full antidepressant efficacy typically requires 4 weeks of treatment at therapeutic doses 3