Pharmacokinetic and safety interactions between aildenafil and clarithromycin, cimetidine, or rifampin in healthy subjects.

Authors

Ran Xie, Nan Zhao, Bo Jia, Lu Cheng, Junyu Xu, Xia Wang, Xia Zhao, Yimin Cui

Published in

British journal of clinical pharmacology. Sep 13, 2026. Epub Sep 13, 2026.

Abstract

Aildenafil citrate, an orally bioavailable phosphodiesterase type 5 (PDE5) inhibitor, is primarily metabolized by cytochrome P450 3A4 (CYP3A4). This study aimed to assess potential pharmacokinetic interactions between aildenafil citrate tablets and cytochrome P450 (CYP)3A modulators.
This study involved three open-label, fixed-sequence trials in healthy subjects. Participants received a single oral dose of aildenafil 60 mg alone and with repeated doses of clarithromycin (500 mg, CYP3A4 inhibitor, N = 18), rifampin (600 mg, inducer, N = 18), or cimetidine (400 mg, N = 18). Pharmacokinetic (PK) parameters-including maximum serum concentration (Cₘₐₓ), area under the concentration-time curve (AUC), time to reach Cₘₐₓ, and half-life (t_1/2)-were calculated using noncompartmental analysis from serial serum aildenafil concentrations. Adverse events were monitored throughout.
Clarithromycin significantly increased aildenafil exposure, with geometric mean ratios (90% CI) of 1.67 (1.51-1.85) for C_max and 2.58 (2.42-2.76) for AUC_0-∞. Conversely, rifampin markedly reduced aildenafil serum concentrations, with geometric mean ratios (90% CI) of 0.02 (0.02-0.03) for C_max and 0.01 (0.01-0.02) for AUC_0-∞. Coadministration with cimetidine resulted in log-transformed C_max and AUC_0-∞ ratios near 1.0 (0.99 and 1.17, respectively), with geometric mean ratios (90% CI) of 0.99 (0.84-1.16) and 1.17 (1.10-1.25), indicating no significant effect on aildenafil exposure.
Coadministration of aildenafil with the strong CYP3A4 inhibitor clarithromycin increased aildenafil AUC_0-∞ by 2.58-fold and C_max by 1.67-fold; therefore, dose adjustment should be guided by clinical response and tolerability. In contrast, coadministration with the strong CYP3A4 inducer rifampin is not recommended.

PMID:
42732925
Bibliographic data and abstract were imported from PubMed on 14 Sep 2026.

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