Evaluation of orally administered telmisartan for the reduction of indirect systolic arterial blood pressure in awake, clinically normal cats.

Abstract

The aim of this study was to compare the effects of multiple once- or twice-daily oral dosage rates of the angiotensin II, type-1 receptor blocker, telmisartan (TEL), or placebo (PLA) on indirect systolic arterial blood pressure (SBP) in awake, clinically normal cats. Utilizing an incomplete crossover design and following a 14 day acclimation period, 28 healthy laboratory cats were randomized to undergo treatment with three of the following 14 day treatment protocols, each separated by a 1 week washout period: oral PLA q24h, oral TEL at a dosage of 1, 1.5, 2 or 3 mg/kg q24h, or oral TEL at a dosage of 1 or 1.5 mg/kg q12h. Using the Doppler ultrasound method, indirect SBP was measured daily during each treatment period, and daily during the first 5 days of each washout period, approximately 3 h after administration of the morning treatment. Each treatment protocol was administered to a total of 12 cats. A statistically significant effect of treatment period was identified for the entire study; therefore, only data from the first treatment period (four cats per treatment group) were used for further analysis. Compared with PLA, during the first treatment period, SBP values were significantly lower in cats treated with TEL at all tested dosages by the second week of treatment. SBP remained significantly lower than in PLA-treated animals for 2 days following administration of the last dose in all TEL treatment groups. No clinical signs of hypotension were noted in any group. These results suggest that treatment with TEL at a total daily dose of 1-3 mg/kg - administered as a single dose, or split into two equal doses administered 12 h apart - results in a significant, relatively long-lasting reduction of SBP in clinically normal cats. TEL appears to be well tolerated by normal cats at the dosages tested.