Trazodone hydrochloride is an antidepressant used in clinical practice. As a substrate of cytochrome P450 enzymes that is vulnerable to P-glycoprotein transport, several factors can alter its plasma concentration, and hence, dose adjustment may be required. The aim of this scoping review was to identify genetic polymorphisms that influence the pharmacokinetics of trazodone hydrochloride.

A literature search was performed using PubMed, PubMed Central, BVS/BIREME, EBSCOhost, Web of Science, Embase, Cochrane Library, and Medline databases for studies published until August 2021. The search strategy was based on the following keywords: Trazodone OR “m-chlorophenyl piperazine” AND “Pharmacogenetics” OR “Genetics” OR “Cytochrome P-450 Enzyme System” OR “Polymorphism, Single Nucleotide” OR “Polymorphism, Genetic.”

The search retrieved 684 candidate articles; 307 duplicates were eliminated. In total, 377 articles were eligible for the first screen. However, only 4 met the eligibility criteria, and 12 polymorphisms in 5 different genes (CYP2D6, CYP1A2, CYP3A4, CYP3A5, and ABCB1). Notably, only C3435T ABCB1 influenced the pharmacokinetics of trazodone hydrochloride. Individuals with the T/T genotype had lower area under the curve, half-life, and maximum concentration values with a higher clearance rate.

Polymorphisms in CYP450 do not seem to directly influence the pharmacokinetics of trazodone hydrochloride or its metabolites. By contrast, genetic polymorphisms in ABCB1 seem to have an important effect on the pharmacokinetics of trazodone hydrochloride by enhancing drug metabolism and elimination.