Trazodone

Trazodone is the most prescribed sleep medication in the United States that was never actually approved as a sleep medication. Built as an antidepressant in the 1960s, came to market in 1981, quietly got demoted to a sedative because at antidepressant doses it knocked everybody out before the mood lift kicked in. Somewhere in the late 90s, psychiatrists started writing it at 25 or 50mg at bedtime for insomnia and it took over the country. About a million prescriptions a month, the vast majority off-label.

It’s a serotonin antagonist and reuptake inhibitor, which basically means it does two things at once. At higher doses it acts like a weak SSRI. At lower doses the antihistamine and alpha-1 blockade dominate, and those are the receptors that make you sleepy. That split-personality pharmacology is why a 50mg dose feels nothing like a 300mg dose, and why most patients on trazodone have never taken anything close to a real antidepressant dose.

I write a lot of it. Most psychiatrists do. Not glamorous, not new, works.

The dose hierarchy nobody explains

Trazodone is one of those drugs where the dose changes what it is. Patients get confused by this because the bottle just says “trazodone 50mg” and doesn’t tell you that 50mg and 300mg are doing fundamentally different jobs in the brain.

At 25 to 50mg, you’re getting almost pure sedation through H1 histamine blockade and alpha-1 adrenergic blockade. That’s the sleep dose. It puts you down, holds you down for six or seven hours, and doesn’t really touch mood. Most people in clinic land somewhere here.

At 100 to 150mg, you’re still mostly using it for sleep but starting to nudge the serotonin system. Some patients get a mild anxiolytic effect at this range, useful when sleep and anxiety are tangled. You also start seeing more morning grogginess.

At 200 to 400mg, you’re using it as an actual antidepressant. Almost nobody tolerates these doses for long because the sedation is brutal. The studies that got it FDA-approved for depression were run at these doses, and it works, we just have a hundred better-tolerated antidepressants now. The original use case basically evaporated and the off-label use case ate the whole market.

The other thing nobody tells patients is that 50mg and 100mg aren’t twice the sedation. The dose-response curve flattens fast. Most people get 95% of the sleep benefit at 50mg and just add side effects by going higher.

Why it became the go-to instead of Ambien

Twenty years ago, if you walked into a primary care office complaining of insomnia, you walked out with Ambien. That’s largely stopped. The FDA black-boxed the Z-drugs for sleepwalking and complex sleep behaviors in 2019, which most prescribers had been worried about for a decade. Patients were eating in their sleep, driving in their sleep, having sex they didn’t remember. The drug class works, but the risk profile got harder to ignore.

Trazodone slid into that vacuum. It has a few things going for it that the Z-drugs and benzos don’t. No physical dependence in any meaningful way. You can stop it. People sometimes get a rebound insomnia for a couple nights, which isn’t real withdrawal so much as the underlying sleep problem coming back, but there’s no shaking, no seizures, none of the benzo nightmare.

No abuse potential either. There’s no street value. Nobody is crushing trazodone to snort it. You can give it to somebody with a history of substance use without losing sleep yourself. And it plays well with antidepressants. Half my insomnia patients are already on an SSRI that’s making sleep worse, and trazodone layers on top without serotonin syndrome being a real concern at sleep doses. That combination, an SSRI for the depression plus low-dose trazodone for the SSRI-induced insomnia, is probably the single most common combo in outpatient psychiatry.

Nobody keeps prescribing trazodone because it’s the best sleep drug. They keep prescribing it because it’s the least bad one we have for long-term use.

Where it loses, and the warning that needs saying

Morning grogginess is the main complaint. Trazodone has a half-life of about seven hours, which sounds fine until you realize somebody who takes it at 11pm still has half of it on board at 6am. A solid third of patients describe the first hour after waking as wading through mud, which improves over a couple weeks but doesn’t always go away.

Compared to Ambien, you don’t get that fast knockout feeling. Trazodone takes 30 to 60 minutes to work and the sedation comes on like a slow tide. Most people who switch from a Z-drug complain about this for a few weeks before they adjust. The flip side is that sleep architecture on trazodone is closer to normal, with more deep sleep preserved, whereas Z-drugs give you a kind of pharmacologically-shaped sleep that doesn’t refresh you the same way.

Then there’s priapism. This is the thing every man on trazodone needs to actually be told about, and a lot of prescribers gloss over it because the rate is around 1 in 6000. The alpha-1 blockade that helps you sleep can, very rarely, cause a sustained, painful erection that doesn’t go away. If it lasts more than four hours, that’s a urological emergency. You go to the ER. If it goes long enough untreated, the tissue damage is permanent, and you may not get a functioning erection back. Small risk, real risk, needs to be named when the prescription is handed over. The patients I’ve seen who weren’t warned about this were the angriest ones I’ve ever had.

Trazodone versus mirtazapine, which is the actual decision

If trazodone is the most-prescribed off-label sleep drug, mirtazapine (Remeron) is the runner-up, and the choice between them is one of the more common micro-decisions in outpatient psychiatry. Both are sedating antidepressants used off-label at low doses for sleep. They do different things underneath.

Mirtazapine is heavier. The 7.5 and 15mg doses hit harder than trazodone 50mg, and it reliably stimulates appetite, which is great for the underweight depressed patient and a problem for everyone else. Patients gain weight on mirtazapine. Not always, but often enough that I bring it up before writing the prescription.

Trazodone is lighter, weight-neutral, and easier to titrate. The downside is the priapism risk in men and the morning grogginess.

The practical sort: if the patient is underweight, has poor appetite, or has severe anxiety on top of insomnia, mirtazapine usually wins. If the patient is already at a healthy weight and just needs sleep, trazodone wins. For men where the priapism conversation is a dealbreaker, mirtazapine. For women, more often trazodone.

The patient who’s been on it for ten years

I have a patient, late 50s, came to me three years ago after her old psychiatrist retired. She’s been on trazodone 100mg at bedtime since 2014. Started it after her divorce when she couldn’t sleep, tried Ambien for a few months, didn’t like how it made her feel, switched to trazodone, never came off.

Every annual visit we have the same conversation. Do you still need this. Have you tried a few nights without it. What happens when you skip a dose. The answer is always the same. She sleeps fine on it, badly off it, has tried tapering twice and bounced both times. No tolerance escalation. Same dose for a decade. Liver and kidneys check out. No falls.

At some point the question stops being “should she be on this forever” and becomes “what’s the cost of taking her off something that’s working.” There isn’t one. Trazodone at low dose has one of the cleanest long-term safety profiles of any psychiatric drug. The version of her without it has worse sleep, worse mood, worse function. So she stays on 100mg and we check in once a year. That’s how most long-term trazodone patients look. A person who sleeps better with a small white pill at bedtime and worse without. There are worse hills to be on in psychiatry.