Trazodone is an antidepressant that’s officially approved to treat major depressive disorder in adults, but it’s prescribed far more often for something else: sleep problems. First approved in 1981, trazodone has become one of the most commonly prescribed medications for insomnia in the United States, even though that use has never received formal FDA approval. It’s also used off-label for anxiety, agitation in dementia patients, and several other conditions.
Depression: The Primary Approved Use
Trazodone’s only FDA-approved indication is major depressive disorder in adults. For depression, the typical starting dose is 150 mg daily, though some doctors begin at 100 mg to reduce the chance of side effects. The dose can go up to 300 mg or higher depending on how you respond.
The timeline for depression relief is not immediate. You may notice some changes in the first week or two, but the full antidepressant effect typically takes four to six weeks. This is similar to other antidepressants and is worth knowing so you don’t give up on the medication too early. Doctors generally recommend giving trazodone at least six weeks before deciding whether it’s working for depression.
Insomnia: The Most Common Off-Label Use
The reason trazodone is so widely prescribed for sleep comes down to how it works in the brain. At low doses (25 to 100 mg), it blocks three types of receptors that promote wakefulness: serotonin receptors, histamine receptors, and adrenaline receptors. This triple-blocking action makes people drowsy, which is actually a side effect when treating depression but becomes the whole point when treating insomnia.
Clinical trials show that 50 mg of trazodone taken at bedtime reduces the time it takes to fall asleep and increases total sleep duration. In one study of 306 adults, trazodone shortened sleep onset significantly more than placebo during the first week of use. A separate study found that 50 mg was effective for staying asleep through the night, though it was possibly associated with some next-day grogginess and motor impairment.
It’s worth noting that the American Academy of Sleep Medicine actually recommends against using trazodone as a first-line treatment for insomnia, citing limited long-term evidence. That recommendation is rated “weak,” meaning the evidence isn’t strong in either direction. Despite this, many doctors still prescribe it for sleep because it’s inexpensive, non-addictive, and carries less risk of dependence than traditional sleep medications. The sleepiness effect kicks in within the first few days of use, making it faster-acting for insomnia than for depression.
Anxiety and Agitation
Trazodone is frequently prescribed off-label for anxiety disorders. For anxiety, doses can go up to 300 mg daily, similar to what’s used for depression. The sedating quality that makes it useful for sleep also helps take the edge off anxiety, particularly the kind that keeps people wired at night.
In older adults with dementia, trazodone has shown modest benefits for behavioral symptoms like agitation, irritability, and restlessness. In a pilot study of 13 patients with Alzheimer’s disease, low-dose trazodone (25 mg three times daily) over 10 weeks reduced irritability, anxiety, restlessness, and emotional disturbances. It did not, however, improve cognitive function. Three separate studies have reported beneficial effects on behavioral disturbances in dementia, making it a common option for caregivers and doctors managing these symptoms.
Other Off-Label Uses
Beyond sleep, depression, and anxiety, trazodone has been used for a range of other conditions. These include post-traumatic stress disorder, fibromyalgia, eating disorders, and substance abuse disorders. The evidence for these uses varies, and trazodone is generally not a first-choice treatment for any of them. But for patients who haven’t responded well to other medications, or who have overlapping problems like depression combined with insomnia, trazodone’s multi-target approach can address several symptoms at once.
How Trazodone Works Differently at Different Doses
One of the more unusual things about trazodone is that its effects change depending on the dose. At low doses (25 to 100 mg), the dominant actions are blocking histamine, serotonin, and adrenaline receptors, which produces sedation. At higher doses (150 mg and above), trazodone also starts blocking the serotonin transporter, which is the mechanism responsible for its antidepressant effect. This is why a person taking 50 mg for sleep and a person taking 300 mg for depression can have quite different experiences with the same drug.
If your dose is 300 mg or less, you’ll likely be told to take it all at once at bedtime, since the sedation helps with sleep and avoids daytime drowsiness. Higher doses may be split throughout the day.
Side Effects to Know About
The most common side effect is drowsiness, which is either a benefit or a problem depending on why you’re taking it. Next-day grogginess, dizziness, and dry mouth are also frequently reported.
For men, there’s a rare but serious risk called priapism, a prolonged, painful erection that requires emergency treatment. This occurs in less than 1% of patients, with incidence estimates ranging from 1 in 1,000 to 1 in 10,000 male patients. About 8% of men in one study experienced prolonged erections that didn’t meet the threshold for priapism but were still notable. This is a side effect to be aware of because delayed treatment can cause permanent damage.
Trazodone can also affect heart rhythm in people with underlying heart disease or those taking medications that influence heart rhythm. This makes it important to disclose your full medication list and cardiac history before starting treatment.
Drug Interactions That Matter
The most dangerous interaction involves combining trazodone with other medications that raise serotonin levels. This can trigger serotonin syndrome, a potentially life-threatening condition that causes agitation, rapid heart rate, high blood pressure, and muscle rigidity. Medications to be cautious about include certain cough suppressants (dextromethorphan, found in many over-the-counter cold medicines), older antidepressants, the supplement tryptophan or 5-HTP, and buspirone. Even some melatonin supplements have been found to contain 5-HTP as a contaminant, which could increase this risk.
Stopping Trazodone
Trazodone can cause withdrawal symptoms if stopped abruptly, especially after long-term use. People who have discontinued the medication report dizziness, anxiety, nausea, headaches, difficulty walking, nightmares, and blood pressure spikes. A gradual taper is the standard approach. One common schedule involves reducing the dose by 12.5 mg every two weeks, though your doctor will adjust this based on your dose and how long you’ve been taking it. The key point is not to stop suddenly on your own.