Prescribing-label excerpts
Trazodone Hydrochloride
Reference for: Trazodone. Source presentation: tablet, film coated. Source route: oral.
Mechanism of action
The mechanism of trazodone’s antidepressant action is not fully understood, but is thought to be related to its enhancement of serotonergic activity in the CNS. Trazodone is both a selective serotonin reuptake inhibitor (SSRI) and a 5HT2 receptor antagonist and the net result of this action on serotonergic transmission and its role in trazodone’s antidepressant effect is unknown.
Pharmacokinetics
Absorption — In humans, trazodone hydrochloride is absorbed after oral administration without selective localization in any tissue. When trazodone hydrochloride is taken shortly after ingestion of food, there may be an increase in the amount of drug absorbed, a decrease in maximum concentration and a lengthening in the time to maximum concentration. Peak plasma levels occur approximately one hour after dosing when trazodone hydrochloride is taken on an empty stomach or 2 hours after dosing when taken with food.
Metabolism — In vitro studies in human liver microsomes show that trazodone is metabolized, via oxidative cleavage, to an active metabolite, m-chlorophenylpiperazine (mCPP) by CYP3A4. Other metabolic pathways that may be involved in the metabolism of trazodone have not been well characterized. Trazodone is extensively metabolized; less than 1% of an oral dose is excreted unchanged in the urine.
Elimination — In some patients trazodone may accumulate in the plasma.
Protein Binding — Trazodone is 89 to 95% protein bound in vitro at concentrations attained with therapeutic doses in humans.
Selected passages from the cited U.S. prescribing label. The studies concern the source product and populations named in each passage; they do not establish Walter-product bioequivalence, an approved indication, or the kinetics of another fixed combination. Tables and the full prescribing information remain available in the source.
Source: DailyMed: Trazodone Hydrochloride — tablet, film coated
Reference accessed . Label revision: 2026-09-03.
