Side Effects of Trazodone
Trazodone's most common side effects are somnolence (drowsiness/sedation), dizziness, headache, and dry mouth, with the sedation being more pronounced than other antidepressants like bupropion, fluoxetine, mirtazapine, paroxetine, or venlafaxine. 1, 2
Common Side Effects
The most frequently reported adverse effects include:
- Somnolence/sedation - This is the predominant side effect and occurs at higher rates than with other second-generation antidepressants 1, 2, 3
- Dizziness - Commonly reported, particularly when changing positions 1, 3
- Headache - Frequent complaint among users 1, 3
- Dry mouth - Common anticholinergic effect, though less severe than with tricyclic antidepressants 3
- Nausea and vomiting - Gastrointestinal effects occur regularly 1, 3
- Diarrhea - Reported in clinical trials 3
- Blurred vision - Visual disturbances can occur 3
- Weight changes - Both weight gain and weight loss have been reported 3
Serious Adverse Effects Requiring Immediate Attention
Cardiovascular Effects
- QT interval prolongation and torsade de pointes - Can occur even at doses of 100 mg/day or less, though relatively rare 2, 3
- Cardiac arrhythmias - Including ventricular tachycardia, atrial fibrillation, and cardiac arrest have been reported 3
- Orthostatic hypotension and syncope - Risk of feeling dizzy or fainting when changing positions, particularly in elderly patients or those with heart disease 3
Priapism
- Prolonged erection lasting more than 6 hours - This is a medical emergency requiring immediate treatment 3
- In one study of 74 male veterans, 5 subjects (approximately 7%) discontinued trazodone due to priapism 1
Neuropsychiatric Effects
- Serotonin syndrome - Symptoms include agitation, hallucinations, coordination problems, fast heartbeat, tight muscles, trouble walking, sweating, fever, nausea, vomiting, and diarrhea 3
- Activation of mania or hypomania - Patients may feel excessively high, irritable, or have excessive energy 3
- Suicidal thoughts and behavior - Particularly in children, adolescents, and young adults 3
- Parkinsonism - Rare cases of tremors, rigidity, and shuffling gait have been reported 4
Hematologic Effects
- Unusual bruising or bleeding - Increased bleeding risk, particularly when combined with NSAIDs, aspirin, or warfarin 3
- Hemolytic anemia - Reported in post-marketing surveillance 3
Other Serious Effects
- Hyponatremia (low sodium) - Symptoms include headache, weakness, confusion, trouble concentrating, memory problems, and feeling unsteady 3
- Angle-closure glaucoma - Eye pain, vision changes, swelling or redness in or around the eye 3
- Hepatotoxicity - Jaundice, cholestasis, and liver enzyme elevations have been reported 3
Discontinuation-Related Side Effects
In the PTSD nightmare study, 14 of 74 patients (19%) discontinued trazodone due to intolerable side effects, which included 1:
- Priapism (5 patients)
- Daytime sedation (5 patients)
- More vivid nightmares (1 patient)
- Dry mouth/sinuses (1 patient)
- Muscle pain (1 patient)
- Severe agitation (1 patient)
Withdrawal symptoms can occur if trazodone is stopped abruptly, including anxiety, agitation, and sleep problems - always taper the medication under medical supervision 3
Important Clinical Considerations
- 60% of patients continuing trazodone in clinical studies experienced some side effect, with daytime sedation and dizziness being most common 1
- Trazodone has minimal anticholinergic activity compared to tricyclic antidepressants, making it potentially better tolerated in elderly patients 2
- Take trazodone shortly after a meal or light snack to optimize absorption and potentially reduce side effects 3
- Avoid alcohol and other CNS depressants as they can worsen drowsiness and dizziness 3
- Caution is required in patients with premature ventricular contractions due to potential cardiovascular effects 2