Trazodone is an antidepressant prescribed off-label at low doses of 25mg to 100mg for insomnia, where it works mainly by blocking histamine H1 and serotonin 5-HT2A receptors. It is among the most commonly prescribed sleep medications in the United States despite the American Academy of Sleep Medicine recommending against its use for sleep-onset or sleep-maintenance insomnia, a recommendation based on limited and low-quality evidence. Common effects are morning grogginess, dizziness on standing, and dry mouth; priapism is rare and a urological emergency. It is not a controlled substance and carries no meaningful dependence risk.
TL;DR: Trazodone is an old antidepressant that doctors prescribe in small doses to help people sleep. It is everywhere, it is cheap, it is not addictive, and it is not a controlled substance. It also has a weaker evidence base than its popularity suggests, and the American Academy of Sleep Medicine recommends against using it for insomnia because the studies are few and small. That does not mean it never helps anyone. It means you should know what you are taking and why. Common effects are morning fog, feeling dizzy when you stand, and a dry mouth. One rare effect, a painful erection lasting hours, is an emergency and needs an ER. The behavioural treatment CBT-I beats it and keeps working after you stop. Tell Dr. Ash how you are sleeping.
Trazodone occupies an odd position in American medicine: one of the most-written sleep prescriptions in the country, and one the sleep specialists' own guideline advises against.
Both of those deserve explaining, because the gap between them is where most patients are standing.
What is trazodone and how does it work for sleep?
Trazodone is a serotonin antagonist and reuptake inhibitor, developed and approved as an antidepressant in the 1980s at doses of 150mg to 400mg a day.
At the much lower doses used for sleep, its antidepressant mechanism is barely engaged and something else does the work. Trazodone blocks histamine H1 receptors, which is the same pathway that makes older antihistamines sedating, and it blocks serotonin 5-HT2A receptors, which promotes deeper slow-wave sleep. It also blocks alpha-1 adrenergic receptors, which contributes to the sedation and to the drop in blood pressure on standing.
The dose separation matters. 50mg for sleep and 300mg for depression behave like two different drugs, and somebody taking the small dose is not being treated for depression.
What dose is used for sleep?
25mg to 100mg at bedtime, with 50mg the most common starting point.
Many people do well on 25mg, and starting low reduces the morning grogginess that is the usual reason for stopping. Above 100mg, the added sedation is modest and the side effects climb, so a person needing more than that is usually a person for whom trazodone is the wrong drug.
Timing is 30 to 60 minutes before bed. The half-life is about 5 to 9 hours, which is long enough to cover a night and long enough to leave some people foggy in the morning if the dose is too high or taken too late.
Why does the sleep guideline recommend against it?
Because there is very little trial evidence, and what exists is small.
The American Academy of Sleep Medicine's 2017 clinical practice guideline on pharmacologic treatment of chronic insomnia issued a recommendation against trazodone for both sleep-onset and sleep-maintenance insomnia, graded weak, on evidence they rated very low quality. Their reasoning was that the small benefit demonstrated did not clearly outweigh the harms, and that the studies were few, short, and mostly in people with depression instead of primary insomnia.
That is an uncomfortable finding for a drug written this often, and there are reasons for the popularity that have nothing to do with efficacy data. Trazodone is inexpensive, is not a controlled substance, requires no prescription monitoring, carries no dependence risk, and arrived at a moment when prescribers were becoming reluctant about benzodiazepines and Z-drugs. It became the default because of what it is not.
None of that means it is useless. Plenty of people sleep better on it and clinical experience is not nothing. It means the plain framing is a drug with a reasonable safety profile, a plausible mechanism, and thin proof, and you are entitled to be told that.
Guidance from the Clinic
What are the side effects?
Morning grogginess. The commonest complaint and usually a dose or timing problem before it is a drug problem.
Dizziness on standing. From alpha-1 blockade. It matters most in older adults, where it contributes to falls, and it is a reason to get out of bed slowly.
Dry mouth, blurred vision, constipation. Mild anticholinergic effects.
Headache and nausea, usually early and often settling.
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Weight change. Less than with some alternatives, and reported.
The serious ones are uncommon and belong on your list:
Priapism. A persistent, painful erection unrelated to arousal. It is rare, on the order of one in several thousand men, and it is a urological emergency: an erection lasting more than four hours needs an emergency department, because delay risks permanent damage.
QT prolongation and arrhythmia, dose-related, so a cardiac history or other QT-prolonging medication changes the calculation.
Serotonin syndrome, if combined with other serotonergic drugs including SSRIs, SNRIs, triptans, tramadol, or linezolid.
Orthostatic falls in older adults, which is the effect that most often turns a sleep aid into a hospital admission.
Who should not take it?
Anyone with a history of priapism, significant QT prolongation, or recent heart attack. Anyone taking a monoamine oxidase inhibitor, or who has taken one within 14 days. Anyone with an existing serotonergic burden that would push toward serotonin syndrome.
Caution, meaning a conversation before it is prescribed, applies to older adults given the fall risk, people with liver disease, people with cardiac conduction disease, and anyone whose sleep problem has not been screened for apnea. That last one is not specific to trazodone and it is the step most often skipped: sedating an unmeasured apnea is covered on insomnia or sleep apnea.
Can you stop it suddenly?
For short-term low-dose use, generally yes. For nightly use over months, taper.
Trazodone does not cause the dependence a benzodiazepine does, and abrupt discontinuation after sustained use can still produce discontinuation symptoms including dizziness, nausea, irritability, and vivid dreams, and rebound insomnia for several nights. A taper over one to two weeks avoids most of it.
Anyone stopping should have a plan for the sleep that comes next, since rebound insomnia is what sends most people straight back onto the drug. Pairing a taper with CBT-I works better than a taper alone.
How Fishtown Medicine approaches it
As a bridge with a review date, inside a membership, and never as an indefinite refill.
What that means in practice: the apnea question is asked first, the reason for the insomnia is worked out, the behavioural treatment starts, and if a medication is used it is chosen for that person and revisited. A sleep drug that has been renewed for years without anybody asking whether it still works is the failure mode this is set up to avoid, and it is why sleep care here runs on a follow-up rhythm. That is on sleep disorders treatment.
Key Takeaways
- Trazodone works for sleep mainly through histamine H1 and serotonin 5-HT2A blockade at doses far below its antidepressant range.
- The AASM recommends against it for insomnia on very low quality evidence, which is a statement about the trials and not proof it fails.
- 25mg to 100mg, 30 to 60 minutes before bed, is the usual approach, and morning fog is usually a dose or timing problem.
- Priapism is rare and is an emergency: more than four hours needs an emergency department.
- Sleep apnea should be screened for before any sedating medication is prescribed.
Related at Fishtown Medicine
Scientific References
- Sateia MJ, Buysse DJ, Krystal AD, Neubauer DN, Heald JL. Clinical Practice Guideline for the Pharmacologic Treatment of Chronic Insomnia in Adults. Journal of Clinical Sleep Medicine. 2017;13(2):307-349.
- Jaffer KY, Chang T, Vanle B, et al. Trazodone for Insomnia: A Systematic Review. Innovations in Clinical Neuroscience. 2017;14(7-8):24-34.
- Mendelson WB. A review of the evidence for the efficacy and safety of trazodone in insomnia. Journal of Clinical Psychiatry. 2005;66(4):469-476.
- US Food and Drug Administration. Desyrel (trazodone hydrochloride) prescribing information. FDA Access Data.
- Thompson JW, Ware MR, Blashfield RK. Psychotropic medication and priapism: a comprehensive review. Journal of Clinical Psychiatry. 1990;51(10):430-433.
- Qaseem A, Kansagara D, Forciea MA, Cooke M, Denberg TD. Management of Chronic Insomnia Disorder in Adults: A Clinical Practice Guideline From the American College of Physicians. Annals of Internal Medicine. 2016;165(2):125-133.
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