Randomized placebo-controlled clinical trial of a chewable formulation of amlodipine for the treatment of hypertension in client-owned cats.
BACKGROUND
There is an unmet clinical need for a cat-specific formulation of amlodipine to treat hypertensive cats.


OBJECTIVES
To assess the efficacy of chewable amlodipine tablets in reducing systolic blood pressure (SBP) in cats diagnosed with systemic arterial hypertension.


ANIMALS
Seventy-seven client-owned cats with systemic hypertension were included (median age 14 years).


METHODS
The study was randomized, double-blinded, and placebo-controlled. Forty-two cats received 0.125-0.50 mg/kg amlodipine once daily for 28 days; 35 cats received placebo. After 28 days all cats continued with amlodipine for 2-3 months in an open-label phase. Blood pressure was measured using high definition oscillometry. A responder was defined as a cat showing a decrease of SBP to <150 mmHg at 28 days or a decrease from baseline ≥15%.


RESULTS
Sixty-one cats completed the study. The responder rate was 63% in amlodipine group and 18% in placebo group. Cats receiving amlodipine were 7.9 (95% CI 2.6-24.1) times more likely to be classified as responders when compared to those receiving placebo (P < .001). From a mean (±SD) baseline value of 181 (±12) mmHg, SBP decreased to 154 (±17) mmHg with amlodipine and to 170 (±21) mmHg with placebo (P < .001). The voluntary acceptance rate of amlodipine formulation was 73%.


CONCLUSIONS AND CLINICAL IMPORTANCE
The chewable amlodipine tablet effectively reduced SBP compared with placebo in hypertensive cats, and was well-tolerated. It can be used concomitantly with angiotensin-converting enzyme inhibitors and in cats with chronic kidney disease.
['Huhtinen|M|M|', 'Derré|G|G|', 'Renoldi|H J|HJ|', 'Rinkinen|M|M|', 'Adler|K|K|', 'Aspegrén|J|J|', 'Zemirline|C|C|', 'Elliott|J|J|']
D000284:Administration, Oral D017311:Amlodipine D000818:Animals D000959:Antihypertensive Agents D002371:Cat Diseases D002415:Cats D004311:Double-Blind Method D005260:Female D006973:Hypertension D008297:Male D013607:Tablets
High definition oscillometry Calcium channel blocker Cardiovascular agents Evidence based medicine Feline