Trazodone’s most common side effect is drowsiness, which affects roughly 24% to 41% of people depending on the setting and dose. Other frequent side effects include dizziness, dry mouth, and blurred vision. Most of these are mild and dose-dependent, meaning lower doses used for sleep tend to cause fewer problems than the higher doses prescribed for depression.
The Most Common Side Effects
In FDA-reviewed clinical trials, the side effects reported most often were drowsiness (24% to 41% of patients), dizziness or lightheadedness (20% to 28%), dry mouth (15% to 34%), and blurred vision (6% to 15%). The wide ranges reflect differences between inpatient and outpatient populations, with outpatients generally reporting higher rates. Headache and daytime sleepiness also show up frequently, particularly at doses above 100 mg per day.
These side effects are dose-dependent. At the low doses commonly prescribed for insomnia (25 to 100 mg), studies have found little to no adverse effects in people without depression. At the higher doses used to treat depression (150 to 600 mg), drowsiness becomes more pronounced and other side effects become more likely. The sedation that makes trazodone useful as a sleep aid is essentially the same mechanism that causes daytime grogginess when doses climb higher.
Blood Pressure Drops and Fall Risk
Trazodone blocks a receptor in the nervous system that helps maintain blood pressure when you stand up. This can cause orthostatic hypotension, a sudden drop in blood pressure that makes you feel dizzy or faint when rising from a seated or lying position. In a study of older adults with high blood pressure, trazodone users experienced a systolic blood pressure drop of nearly 24 mmHg immediately after standing, compared to about 14 mmHg in non-users.
The fall risk is real. In that same study, the combined rate of fainting and falls was 58% among trazodone users versus 21% among non-users. This is especially relevant for older adults, who are already more vulnerable to falls and their consequences. If you’re over 65 or have a heart condition, this side effect deserves particular attention.
Heart Rhythm Changes
Trazodone can affect the heart’s electrical system by interfering with potassium channels that help regulate heartbeat timing. This can lead to a prolonged QT interval, a measurable delay in the heart’s recharging cycle that increases the risk of abnormal rhythms. In rare cases, this has progressed to a dangerous rhythm called torsades de pointes, which can be fatal.
The risk increases if you have existing heart failure, electrolyte imbalances (low potassium or magnesium), or if you take other medications that also affect heart rhythm. Diuretics, certain antibiotics, and methadone are among the drugs that can compound this risk.
Priapism
One of the more unusual risks of trazodone is priapism, a prolonged, painful erection that lasts more than four hours and occurs without sexual arousal. This is a medical emergency. If not treated promptly, it can cause permanent tissue damage. The estimated incidence is between 1 in 1,000 and 1 in 10,000 men taking the medication, making it uncommon but serious enough that men starting trazodone should know the warning signs.
Serotonin Syndrome Risk
Trazodone increases serotonin activity in the brain, which means combining it with other serotonin-boosting substances can push levels dangerously high. This condition, called serotonin syndrome, produces a recognizable pattern: changes in mental clarity, muscle twitching or rigidity, and signs of an overactive nervous system like rapid heart rate and heavy sweating.
Mild cases might look like subtle confusion with a fast heartbeat. Moderate cases bring high blood pressure, agitation, and exaggerated reflexes. Severe cases can escalate into muscle rigidity, dangerously high blood pressure, and organ failure. The medications most likely to interact include other antidepressants, certain pain relievers (particularly synthetic opioids like fentanyl), migraine drugs, anti-nausea medications, and even some dietary supplements like St. John’s wort. No lab test can confirm serotonin syndrome. It’s diagnosed based on symptoms, so recognizing the triad of mental changes, muscle abnormalities, and autonomic overactivity is important.
Weight Changes
Unlike many antidepressants, trazodone does not appear to cause significant weight gain. In a six-week clinical trial comparing trazodone to amitriptyline (an older antidepressant known for weight gain), trazodone did not produce the same effect. Patients who were already overweight actually experienced a slight weight loss on trazodone, while those on amitriptyline gained significantly more. This makes trazodone a relatively neutral option for people concerned about antidepressant-related weight changes.
Suicidal Thoughts in Young Adults
Trazodone carries the same FDA boxed warning that applies to all antidepressants: an increased risk of suicidal thoughts and behaviors in people under 25. This warning is based on pooled data from roughly 77,000 adult and 4,500 pediatric patients across multiple antidepressant trials. The elevated risk was found in patients under 18 and those aged 18 to 24. In patients 25 and older, this increased risk was not observed. This doesn’t mean trazodone causes suicidal behavior in most young people, but it does mean anyone in this age group should be monitored closely, especially during the first weeks of treatment.
What Happens When You Stop Taking It
Stopping trazodone abruptly can trigger withdrawal symptoms, even though it’s not considered addictive in the traditional sense. Common withdrawal effects include anxiety, irritability, dizziness, nausea, headaches, fatigue, insomnia, sweating, and mood swings. Some people experience vivid dreams or confusion. In rare cases, seizures have been reported.
Symptoms typically appear within the first one to three days after stopping, peak around days four through seven, and fade after the first week or two. Some people continue to have mood swings or sleep disturbances for several weeks. The standard approach is a gradual taper, reducing the dose by 10% to 25% every one to two weeks. The final steps often involve very small reductions, such as going from 25 mg to 12.5 mg, before stopping completely. The entire process can take several weeks to a few months depending on how long you’ve been on the medication and your dose.