Single-dose pharmacokinetics of telmisartan oral solution and effect of feeding in dogs

Telmisartan is an angiotensin II receptor blocker that has great potential to improve the treatment of hypertension, proteinuria, and cardiovascular disease in dogs. A feline-approved telmisartan oral solution (TOS) is available, but this formulation has not been evaluated in dogs. The aims of this study were to establish the pharmacokinetics of telmisartan administered as TOS and determine the effect of feeding on drug absorption in dogs. In a cross-over design, seven healthy dogs received 1 mg/kg telmisartan orally as TOS with or without food and underwent serial measurement of plasma telmisartan concentrations over 24 h. Bioequivalence of TOS administered with vs. without food was assessed by the 90% confidence interval method for maximum concentration (C_max ), and the observed and extrapolated areas under the curve (AUC_0-t and AUC_0-∞ ). The mean ratios of these parameters were 0.97 (CI 0.74-1.27), 0.92 (0.81-1.03), and 0.90 (0.82-1.00), respectively. Feeding methods were not bioequivalent based on C_max due to interindividual variation. These results suggest that TOS can be given to dogs with or without food but should be administered in the same way consistently. Additional pharmacokinetic and pharmacodynamic studies are warranted to confirm this recommendation and establish the therapeutic targets for telmisartan in dogs.