Trazodone’s most common side effects are drowsiness, dizziness, and dry mouth, reported by roughly 20% to 40% of people taking the drug depending on the dose. It’s widely prescribed both as an antidepressant and as a sleep aid, and the side effects you experience depend largely on which dose range you’re taking. Most side effects are manageable, but a few rare ones require immediate attention.
Drowsiness, Dizziness, and Dry Mouth
In FDA clinical trials, drowsiness affected about 24% of inpatients and 41% of outpatients. Dizziness or lightheadedness hit roughly 20% to 28%, and dry mouth affected 15% to 34%. These three side effects are by far the most frequently reported, and they stem directly from how trazodone works in the brain. The drug blocks histamine receptors (the same ones targeted by allergy medications that make you sleepy) and alpha-1 adrenergic receptors, which help regulate blood pressure. That combination produces strong sedation and can cause blood pressure to drop when you stand up quickly.
Other commonly reported effects include blurred vision, confusion, unusual tiredness, muscle pain, an unpleasant taste in the mouth, and sweating. These tend to be most noticeable in the first few weeks of treatment and often improve as your body adjusts.
How Dose Affects What You Feel
Trazodone behaves quite differently at low doses compared to high ones. At 25 to 100 mg, the dose most often prescribed for sleep, sedation is the dominant effect. The drug’s sleep-promoting action kicks in at these lower doses because it only needs to block a couple of receptor types to make you drowsy.
At higher doses (150 to 600 mg), trazodone starts working as a full antidepressant, but side effects also intensify. Orthostatic hypotension, the dizzy, faint feeling when you stand up too fast, becomes more pronounced. Sedation can also increase to the point where it interferes with daytime functioning. This tolerability gap is a big reason many people take trazodone only for sleep rather than depression.
Blood Pressure Drops and Fall Risk
Trazodone’s tendency to lower blood pressure when you change positions is more than just uncomfortable. For older adults, it’s a genuine safety concern. Drowsiness, dizziness, confusion, and sudden blood pressure drops all contribute to an elevated fall risk, which is why trazodone appears on medication fall-risk lists used in long-term care settings. Blurred vision and weakness compound the problem.
If you’re over 65 or care for someone who is, this side effect deserves serious attention. Falls in older adults frequently lead to fractures and hospitalizations. Starting at a low dose and getting up slowly from chairs or beds can reduce the risk, but the effect doesn’t always disappear with time.
Heart Rhythm Changes
Trazodone can prolong the QT interval, a measure of electrical activity in the heart. When the QT interval stretches too long, it raises the risk of dangerous irregular heartbeats. Clinical studies have linked trazodone to these rhythm disturbances even at prescribed doses, though the risk is significantly higher in overdose situations.
People with existing heart conditions, those taking other medications that affect heart rhythm, or anyone with low potassium or magnesium levels face a higher risk. Symptoms of a heart rhythm problem include a racing or pounding heartbeat, sudden dizziness, or fainting. This is one of the rarer side effects, but it’s the reason your prescriber may want to review your full medication list before starting trazodone.
Priapism
Trazodone is the antidepressant most commonly associated with priapism, a prolonged, painful erection lasting more than four hours that occurs without sexual stimulation. The estimated incidence is between 1 in 1,000 and 1 in 10,000 users. While that makes it uncommon, it qualifies as a medical emergency. Untreated priapism can cause permanent tissue damage. Anyone experiencing an erection that won’t resolve should seek emergency care immediately, regardless of how unlikely it seems to be connected to their medication.
Weight Changes
Trazodone’s effect on weight is modest in either direction. In clinical trials, about 5% of people gained weight while 6% lost weight, making it relatively weight-neutral compared to many other antidepressants. If you’ve had trouble with weight gain on other medications, trazodone is less likely to cause that problem, though individual responses vary.
FDA Boxed Warning on Suicidal Thinking
Like all antidepressants, trazodone carries an FDA boxed warning about an increased risk of suicidal thinking and behavior in children and adolescents. This risk was identified across a combined analysis of short-term trials of nine antidepressant drugs in young people being treated for depression and other psychiatric conditions. The warning applies most strongly during the first few months of treatment or whenever the dose is changed. Signs to watch for include worsening mood, agitation, irritability, and unusual changes in behavior.
Serotonin Syndrome Risk
Combining trazodone with other drugs that raise serotonin levels can trigger serotonin syndrome, a potentially life-threatening condition where the brain gets flooded with too much serotonin at once. Symptoms come on quickly and include agitation, rapid heartbeat, high blood pressure, dilated pupils, muscle twitching, and in severe cases, high fever and seizures.
The drug classes that pose the highest risk when combined with trazodone include other antidepressants (especially SSRIs and SNRIs), migraine medications called triptans, certain pain medications, and the herbal supplement St. John’s wort. If you take trazodone alongside any of these, the risk isn’t guaranteed, but awareness of early symptoms matters.
Stopping Trazodone
Quitting trazodone abruptly can cause a discontinuation syndrome, with symptoms typically appearing within a few days. Common withdrawal effects include anxiety, irritability, dizziness, nausea, headaches, fatigue, insomnia, sweating, and mood swings. The emotional symptoms can feel particularly unsettling because trazodone is often prescribed to manage anxiety and sleep problems in the first place, so their sudden return can be hard to distinguish from a relapse.
Tapering gradually, reducing the dose in steps over weeks, significantly reduces the chance and severity of withdrawal symptoms. The longer you’ve been on trazodone and the higher your dose, the more important a slow taper becomes.