Comparison of the effects of imidapril and enalapril in a prospective, multicentric randomized trial in dogs with naturally acquired heart failure.

OBJECTIVE: To compare the efficacy and tolerability of the long-term administration of two different angiotensin-converting enzyme inhibitors, imidapril and enalapril, in a multicentric, prospective, randomized parallel-group scheme clinical trial in dogs with naturally acquired heart disease. ANIMALS: One hundred twenty eight dogs with clinical signs of heart failure (stage II (64-50%) - III (45-35%) - IV (19-15%) New York Heart Association) caused by chronic valvular disease or dilated cardiomyopathy were selected. PROCEDURE: Imidapril (minimum dosage 0.25 mg/kg) or enalapril (median dosage 0.5 mg/kg) was administered orally once daily for 12 months, either alone or as an add-on therapy to diuretics and/or digoxin. RESULTS: The primary outcome measure was the quality of life score after 3 months of therapy. Sixty-one percent of the dogs in the imidapril group (36/59) and 52 % in the enalapril group (30/58) were considered responders. After 12 months, a clear improvement compared to baseline was maintained in each treatment group for most parameters reflecting the quality of life such as fatigue, exercise tolerance, dyspnea, cough and general condition. Quality of life scores and survival times were similar in both groups after 12 months. Both drugs were well tolerated over the one-year follow-up. CONCLUSIONS: Imidapril proved to be as effective as the reference drug enalapril in the treatment of dogs with NYHA class II-IV heart failure. As with enalapril, imidapril was well tolerated during the long-term treatment period of one year in the dose range used in the study.

Long-term tolerance of imidapril in the cat.

OBJECTIVES: : To determine the long-term tolerance of imidapril HCl, a novel angiotensin-converting enzyme inhibitor (ACEi), after repeated administrations in the cat. BACKGROUND: : ACEi's are the first-line treatment for congestive heart failure in small animals. They are believed to have potential protective effects on kidney, especially in cats. As they are used for chronic pathologies, their long-term tolerance has to be proven before clinical studies may be performed. METHODS: : To determine chronic tolerance, 24 cats were administered 0.5, 1.5 or 5 mg/kg/day of imidapril or a placebo for 3 months. Cats were subjected to clinical examination, cardiovascular follow-up (ECG and blood pressure determination), haemato-biochemistry and urinalysis. A toxicokinetic follow-up was carried out, and a complete necropsy performed at the end of the study. RESULTS: : After three months of administration, there were no clinical, cardiovascular, haemato-biochemical, or urinary adverse effect. At necropsy, cats from the high dose group (5 mg/kg/day) showed a slight hypertrophy of the juxtaglomerular apparatus with increased granulation. This was considered to be a pharmacological rather than a toxic effect. CONCLUSIONS: : No sign of toxicity was seen during this study. As preclinical data suggested that pharmacodynamic effect in the cat was obtained with a posology of 0.5mg/kg/day, imidapril can be considered as perfectly safe for long-term administration in the cat.