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CYP3A5 genetic variability influences sildenafil and metabolite in pulmonary hypertension

Wongwien P, Pussadhamma B, Kanjanawart S, Areesinpitak T, Nakkam N, Foocharoen C, Tassaneeyakul W, Vannaprasaht S

British journal of clinical pharmacology, 2026

92 participants

Abstract

Aim: Interindividual variability in sildenafil response among pulmonary hypertension patients (PH) may be influenced by CYP3A5 polymorphisms. CYP3A5*3 allele reduces CYP3A5 activity and affects sildenafil metabolism. This study investigated the associations between CYP3A5 genotype and plasma concentrations of sildenafil and N-desmethyl sildenafil, as well as clinical outcomes, in PH.

Methods: A cross-sectional study of 92 patients with PH was conducted. Blood samples were collected at trough and 1 h after sildenafil administration (C1h). Plasma concentrations were quantified by HPLC, and CYP3A5 genotypes were determined by real-time PCR with TaqMan probes.

Results: Thirteen (14.13%) patients carried the CYP3A5 *1/*1 genotype, and 79 (85.87%) carried the CYP3A5*3 allele. CYP3A5*3 allele carriers had a significantly higher mean C1h sildenafil concentration-to-dose (C/D) ratio than CYP3A5*1/*1 carriers (3.61 ± 2.69 vs. 2.66 ± 1.20 ng/mL/mg; p = 0.043). The mean C1h of sildenafil, trough sildenafil concentration and trough sildenafil C/D ratio were higher in CYP3A5*3 carriers, but not statistically significant. The trough and C1h of N-desmethyl sildenafil and their corresponding C/D ratios were lower in CYP3A5*3 carriers but did not reach statistical significance. CYP3A5*3 allele carriers showed greater improvement in 6-min walk distance (33.74 ± 43.46 m vs. -5.58 ± 44.52 m; p = 0.005), WHO functional class (32.00% vs. 15.39%; p = 0.042) and EmPHasis-10 scores (-4.15 ± 6.46 vs.…

How strong is the evidence?

Evidence Hub reads this as a cross-sectional. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause. Reported size: 92 participants or records.

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