Effects of the calcium channel antagonist amlodipine in cats with surgically induced hypertensive renal insufficiency

Objective-To determine whether amlodipine besyate decreases systemic arterial blood pressure (BP) and reduces the prevalence of complications in cats with induced hypertensive renal insufficiency. Animals-20 cats with partial nephrectomy. Procedure-Following reduction in renal mass, 10 cats were administered 0.25 mg of amlodipine/kg, PO, q 24 h (group A). Ten cats served as a control group (group C). Systolic BP (SBP), diastolic BP (DBP), and mean BP (MBP), physical activity, and pulse rate were measured continuously for 36 days by use of radiotelemetric devices. Results-Compared with values for clinically normal cats, SBP DBP and MBP were significantly increased in cats of group C. Cats in group A had significant reductions in SBP DBP and MBP compared with values for cats in group C. Albuminuria but not urine protein-to-creatinine ratio was significantly correlated (R-2 = 0.317) with SBP in hypertensive cats. Prevalence of ocular lesions attributable to systemic hypertension in group C (7 cats) was greater than that observed in group A (2). Two cats in group C were euthanatized on day 16 because of nuerologic complications attributed to systemic hypertension. One normotensive cat in group A was euthanatized because of purulent enteritis of unknown cause on day 27 Conclusions and Clinical Relevance-Amlodipine had an antihypertensive effect in cats with coexistent systemic hypertension and renal insufficiency. Its use may improve the prognosis for cats with systemic hypertension by decreasing the risk of ocular injury or neurologic complications induced by high BP.