Pharmacokinetics of acetaminophen and ibuprofen when coadministered with telmisartan in healthy volunteers

Abstract

Two open-label, two-way, crossover studies were performed to assess any pharmacokinetic interaction of telmisartan with either acetaminophen or ibuprofen. Healthy male adult volunteers (n = 12) received a single oral dose of acetaminophen 1 g alone and with oral telmisartan 120 mg in one study. Oral ibuprofen 400 mg three times daily with and without oral once-daily telmisartan 120 mg was given for 7 days in the other study conducted in 6 males and 6 females. In both studies, there was a washout period of > or = 13 days between single and combination medication administration. The primary end points Cmax and AUC were compared between combination (acetaminophen or ibuprofen + telmisartan) and single-agent medication (acetaminophen or ibuprofen). Pharmacokinetic drug interaction was assessed by analysis of variance (ANOVA) and calculation of 90% confidence intervals (CI) for treatment ratios using log-transformed parameters. Bioequivalence (i.e., lack of interaction) was concluded if the 90% CI of the ratios for both Cmax and AUC were within the acceptance limit of 0.80 to 1.25. Geometric mean Cmax values for acetaminophen and R-(-)- and S-(+)-ibuprofen enantiomers were similar with and without telmisartan coadministration (12.6 micrograms/mL vs. 14.1 micrograms/mL; 17.3 micrograms/mL vs. 16.7 micrograms/mL; 19.4 micrograms/mL vs. 19.5 micrograms/mL, respectively), and values for R-(-)- as well as S-(+)-ibuprofen were bioequivalent. Geometric mean AUC values for acetaminophen and R-(-)- and S-(+)-ibuprofen were also bioequivalent with and without telmisartan. The distribution and elimination parameters of both acetaminophen and ibuprofen were comparable in the presence or absence of telmisartan. The concomitant and single-agent medications were all well tolerated. In conclusion, the long half-life and excellent safety profile of telmisartan were unaffected by concurrent acetaminophen or ibuprofen medication; thus, once-daily dosing of telmisartan can be maintained, which may help to optimize patient compliance, and patients may self-administer concomitant acetaminophen or ibuprofen.