The normal dose of trazodone depends entirely on what it’s being prescribed for. For depression, the starting dose is 150 mg per day taken in divided doses, with a maximum of 400 mg per day for outpatients. For sleep problems, which is the most common reason people take it today, doses are much lower: typically 25 to 50 mg at bedtime. For anxiety, the usual starting dose is 75 mg daily.
These wide differences aren’t arbitrary. Trazodone works on different brain receptors at different doses, which is why the same pill can serve as a sleep aid at one strength and an antidepressant at another.
Why the Dose Varies So Much by Condition
At low doses (around 25 to 50 mg), trazodone primarily blocks two types of receptors in the brain that promote wakefulness and arousal. This is what makes it effective as a sleep aid. It also partially activates a serotonin receptor involved in calming and relaxation. These are trazodone’s most sensitive targets, meaning they respond even to small amounts of the drug.
At higher doses (150 to 300 mg and above), trazodone begins doing something additional: it starts blocking the reabsorption of serotonin, the same mechanism that traditional antidepressants use. It also engages histamine receptors and additional serotonin receptor subtypes. This layered activity is why researchers describe trazodone as a “multifunctional drug” with dose-dependent effects. You’re not just getting more of the same thing when the dose goes up; you’re recruiting entirely different actions in the brain.
Dosing for Depression
The FDA-approved starting dose for major depressive disorder in adults is 150 mg per day, split into two or more doses throughout the day. Your prescriber may increase this by 50 mg every three to four days based on how you respond. Most outpatients stay at or below 400 mg per day. In hospital settings, where patients can be monitored more closely, the maximum goes up to 600 mg per day in divided doses.
The antidepressant effect typically requires doses of at least 150 mg daily to meaningfully block serotonin reuptake. This is a key distinction: if you’re taking 50 mg at bedtime for sleep, you’re not getting a therapeutic antidepressant dose.
Dosing for Sleep
Trazodone is not FDA-approved specifically as a sleep medication, but it’s one of the most commonly prescribed drugs for insomnia in practice. Doses for sleep typically range from 25 to 50 mg, taken once at bedtime. Some people take up to 100 mg for sleep, though the sedating effect doesn’t always scale linearly with the dose.
The drug reaches peak blood levels about one to two hours after you take it. Eating food around the same time slows absorption and lowers the peak concentration somewhat, pushing the time to peak effect closer to two hours. The drug stays active in your system for roughly seven to eight hours (its elimination half-life is about 7.3 hours), which aligns well with a full night of sleep without heavy next-morning grogginess for most people.
Dosing for Anxiety
When prescribed off-label for anxiety, the typical dose is 75 mg per day according to NHS guidelines. This can be increased up to 300 mg daily depending on the severity of symptoms and how well you tolerate the medication. This puts anxiety dosing in a middle range between the low sleep doses and the higher antidepressant doses.
Older Adults
Studies haven’t identified specific geriatric dose limits for trazodone, and extended-release formulations appear to work without unique age-related problems. That said, older adults are more prone to low sodium levels (hyponatremia) while taking trazodone, and they’re also more susceptible to one of the drug’s main side effects: drops in blood pressure when standing up. For these reasons, prescribers often start older patients at the lower end of the dosing range and increase more cautiously.
Side Effects That Scale With Dose
Drowsiness is the most predictable side effect at any dose, and it’s actually the desired effect when trazodone is used for sleep. Beyond that, a few side effects become more relevant as the dose climbs.
Orthostatic hypotension, a sudden drop in blood pressure when you stand up that can cause dizziness or fainting, is tied to trazodone’s effect on certain receptors in blood vessels. This is more likely at higher doses and is one reason the drug is taken in divided doses for depression rather than all at once.
Priapism, a painful erection lasting more than six hours, is rare but serious. It has been reported in men taking trazodone at various doses and requires immediate medical attention because it can cause permanent damage to erectile tissue. In overdose situations, the most frequently reported symptoms are drowsiness and vomiting, while more severe reactions include seizures and heart rhythm changes.
Tapering Off Trazodone
If you’ve been taking trazodone regularly and want to stop, a gradual reduction is safer than quitting abruptly. Stopping suddenly can cause discontinuation symptoms, which may include irritability, anxiety, and sleep disruption. A common approach is reducing the dose by about 25% at a time, holding at each new level for one to two weeks before cutting again. If you’re on a higher dose, the tapering process takes longer but is generally straightforward with a structured plan from your prescriber.