Efficacy of telmisartan for the treatment of persistent renal proteinuria in dogs: A double-masked, randomized clinical trial

Background Information regarding efficacy of the angiotensin II receptor blocker, telmisartan, for treatment of proteinuria in dogs is limited. Objective To evaluate the antiproteinuric efficacy of telmisartan, as compared to enalapril, in dogs with chronic kidney disease and persistent, renal proteinuria. Animals Thirty-nine client-owned dogs with chronic kidney disease and urinary protein-to-creatinine ratio (UPC) > 0.5 (if azotemic) or >= 1.0 (if nonazotemic). Methods In this prospective, randomized, double-masked clinical trial, dogs were block randomized, according to presence or absence of azotemia and systemic arterial hypertension, to receive telmisartan (1.0 mg/kg PO q24h), or enalapril (0.5 mg/kg PO q12h), and followed for 120 days. Up-titration of study drug dosage on days 30 and 60, and addition of the other study drug at day 90, were performed if UPC > 0.5 was noted at these visits. Percentage change in UPC relative to baseline was calculated for all time points. Data are presented as median (range). Results Thirty-nine (20 telmisartan-treated, 19 enalapril-treated) dogs were included. At day 30, percentage change in UPC was greater for telmisartan-treated (-65% [-95% to 104%]) vs enalapril-treated (-35% [-74% to 87%]) dogs (P = .002). Among dogs persistently proteinuric at earlier visits, telmisartan remained superior to enalapril at days 60 (P = .02) and 90 (P = .02). No difference in percentage change in UPC between study groups was observed at day 120, when combination therapy was allowed. Combination therapy resulted in relevant azotemia in 4/13 (31%) dogs. Conclusions and Clinical Importance Telmisartan might be a suitable first-line therapy for dogs with renal proteinuria.