Trazodone

Trazodone is a second-generation antidepressant classified as a serotonin antagonist and reuptake inhibitor, a category defined by its combination of serotonin-2 receptor blockade with weaker inhibition of serotonin reuptake ^[1][2]. Chemically it is a triazolopyridine and a phenylpiperazine derivative, structurally distinct from the older tricyclic antidepressants and the monoamine oxidase inhibitors ^[1]. It was developed in Italy in the 1960s by the Angelini research laboratories and reached the United States in 1981, where it was the first non-tricyclic, non-MAOI antidepressant to be approved ^[1].

Its labeled indication is major depressive disorder, but in practice trazodone is used most often at lower doses as a sleep aid, an off-label application that has come to exceed its use as an antidepressant ^[3]. Systematic reviews support its effectiveness for both primary insomnia and insomnia occurring alongside depression or dementia, and it is also used to augment other antidepressants and to help counter the insomnia or sexual side effects sometimes caused by SSRIs ^[1][3]. Additional off-label uses include anxiety, agitation, and chronic pain ^[1]. It is available as immediate-release and extended-release tablets, marketed under brand names including Desyrel, Oleptro, and Trittico, and it is widely available as a generic.

Trazodone is metabolized in the liver, chiefly by the enzyme CYP3A4, and one of its metabolites, meta-chlorophenylpiperazine (mCPP), is itself active on serotonin systems ^[1][2]. Its relatively short half-life and sedating profile suit its use for sleep. Compared with older antidepressants it causes little in the way of anticholinergic effects, weight gain, or sexual dysfunction ^[2]. The most prominent side effect is drowsiness, and its blockade of alpha-1 adrenergic receptors can cause a drop in blood pressure on standing, raising the risk of dizziness and falls, especially in older adults ^[1]. A rare but important adverse effect is priapism, a prolonged and painful erection that requires urgent care, and the drug can occasionally affect heart rhythm, including QT-interval prolongation ^[1].

Trazodone is a serotonergic antidepressant widely used off-label at low doses for sleep; common effects are sedation, next-day drowsiness, dizziness, dry mouth, and orthostatic hypotension with a fall risk, especially in older adults. It can rarely cause priapism, a urologic emergency, along with QT-interval prolongation and serotonin syndrome when combined with other serotonergic agents. It carries the antidepressant class warning for suicidal thinking in younger patients and should not be combined with MAO inhibitors.

Trazodone is a serotonergic agent and its label contraindicates concurrent or recent (within 14 days) monoamine oxidase inhibitors, and warns of serotonin syndrome when combined with SSRIs, SNRIs, triptans, tramadol, linezolid or other serotonergic drugs. It is primarily metabolized by CYP3A4, so strong CYP3A4 inhibitors (ketoconazole, ritonavir, itraconazole, clarithromycin, grapefruit) raise trazodone and mCPP levels and increase toxicity risk, while CYP3A4 inducers such as carbamazepine lower its exposure. Trazodone prolongs the QT interval, giving additive arrhythmia risk with other QT-prolonging drugs, and its sedative and alpha-1 blocking actions produce additive CNS depression with alcohol, benzodiazepines and opioids plus additive hypotension with antihypertensives. It can also raise plasma digoxin and phenytoin concentrations. This is research information, not medical advice.

Checking a whole stack? Run it through interactions + stacks.

Trazodone was developed in Italy by the research laboratories of Angelini Francesco during the 1960s, emerging from a distinctive line of thinking about depression as a disorder linked to lowered tolerance of mental pain. A phenylpiperazine compound, it was the first of the serotonin antagonist and reuptake inhibitor, or SARI, class, combining blockade of certain serotonin receptors with weak inhibition of serotonin reuptake and sedating actions at histamine and adrenergic receptors.

After establishing itself in Europe, it was approved in the United States in 1981, where it held the distinction of being one of the first widely used antidepressants that was neither a tricyclic nor a monoamine oxidase inhibitor. Although marketed for depression under names such as Desyrel and, in an extended-release form, Oleptro, it found its largest real-world use off-label as a sleep aid, a role built on its pronounced sedating properties at low doses. It remains among the most commonly prescribed medications for insomnia in many countries.

Trazodone is widely appreciated as a versatile and pragmatic medicine, best known today as a low-dose sleep aid that many clinicians favor because it is not a controlled substance and carries little risk of dependence. Its appeal for insomnia rests on its sedating blockade of histamine and serotonin 5-HT2A receptors, which can help people fall and stay asleep without the tolerance concerns associated with some hypnotics.

At higher, antidepressant doses it offers a receptor profile distinct from the SSRIs, and it is often noted for a comparatively low burden of sexual side effects, a meaningful advantage for some patients. Candor requires mentioning its trade-offs, including morning grogginess, dizziness on standing from its blood-pressure-lowering action, and a rare but well-recognized risk of prolonged erections that warrants prompt attention. Taken together, its flexibility, favorable dependence profile, and long track record keep it a trusted and frequently chosen option.