Research Communications of the 24th ECVIM-CA Congress

Seventy-seven client-owned hypertensive cats were enrolled into a randomized, double-blind and placebo controlled study consisting of two phases. In phase one, 42 cats (Group A) received 0.125 mg/kg amlodipine once daily for 14 days. If they were deemed to have responded (see below) the dose remained the same to day 28. For non-responders, the dose was increased to 0.25 mg/kg. Thirty-five cats (Group B) received placebo following the same protocol. Blood pressure was measured using high definition oscillometry. A responder was defined as a cat showing a decrease of systolic blood pressure (SBP) to ≤150 mmHg or a decrease from baseline of ≥15%. Following day 28 (phase 2), Group A continued on amlodipine and Group B switched to amlodipine and the dose was adjusted as per phase 1. Both groups were followed for 90 days on amlodipine. Blood was collected at days 28 (Group A) and 90 (both Groups) and serum [amlodipine] measured by liquid chromatography mass spectrometry. The SBP measured on treatment was calculated as percentage of the baseline SBP and plotted against serum [amlodipine] using a sigmoidal Emax model (WinNonLin software). Data are expressed as mean AE SE.