RESEARCH COMMUNICATIONS OF THE 28th ECVIM-CA CONGRESS

Myxomatous Mitral Valve Disease (MMVD) is the most common heart disease in dogs of small breeds. Amlodipine is a calcium channel blocker that can be beneficial on the treatment of heart failure (HF), due to arterial vasodilator effect, but the adverse effects in patients with MMVD are unclear. The aim of this study is evaluate the adverse effects of amlodipine on the treatment of dogs with MMVD stage C. This is a clinical trial randomized double‐blinded placebo‐control study, that all dogs receive conventional therapy to MMVD stage C (furosemide, spironolactone, enalapril and pimobendan), and randomized in two groups: amlodipine or placebo. The amlodipine mean dose is 0.3 mg/kg once a day. The dogs are followed during 10 months, with clinical assessment, echocardiogram, measurement of systemic arterial blood pressure (SABP) and serum biochemistry. The main side effect of amlodipine is the hypotension that may lead to increase of serum creatinine and BUN, therefore the adverse effects of amlodipine have been assessed by measurement of systolic SABP (by vascular Doppler method) and serum creatinine and BUN. Systolic SABP was measured at the first day of treatment with amlodipine or placebo (T0), seven days (T7D), one month (T1M) and three months (T3M) after the beginning of the treatment. Serum creatinine and BUN were measured at times T0 and T7D. Up to the present time it have already been enrolled 14 dogs in this study. There was no difference in systolic SABP between amlodipine and placebo groups at the four times assessed (p>0.05). There was no difference in systolic SABP in the placebo group among the four times too (p>0.05). The amlodipine group presented a significant increase of systolic SABP between T0 and T7D (p=0.003) and significant decrease between T1M and T3M (p=0.003). No dog (of the both groups) presented hypotension (systolic SABP < 90 mmHg) in the four times of evaluation. Creatinine and BUN serum values didn't present difference in the amlodipine group between T0 and T7D (p>0.05) and the same result was observed in the placebo group (p>0.05). There was also no difference to creatinine and BUN values between the groups for T0 and T7D (p>0.05). This preliminary results showed that amlodipine at the used dose don't induce hypotension or decrease of systolic SABP when compared to placebo group, and don't increase serum creatinine and BUN values during the seven first days of treatment.