Open Veterinary Journal

Open Veterinary Journal

Peer-Reviewed Journal 
ISSN 2218-6050 (Online), ISSN 2226-4485 (Print) 

"Short Communication"

A retrospective study of 14 dogs with advanced heart failure treated with loop diuretics and hydrochlorothiazide

Koji Iwanaga(1), Ryuji Araki(1,2,3) and Mitsuhiro Isaka(3*)

1- Tokyo Veterinary Cardiology Center, 8912 Izumi Building 2F, Fukazawa, Setagaya, Tokyo 1580081, Japan

2- Yokohama Yamate Dog & Cat Medical Center, 274 Kasiwaba Nakaku Yokohamasi Kanagawaken 2310866, Japan

3- Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, 582 Bunkyodai-Midorimachi, Ebetsu, Hokkaido 069–8501, Japan


Background: The use of thiazide diuretics is recommended in the American College of Veterinary Internal Medicine guidelines for advanced heart failure due to mitral insufficiency (MI) in dogs. However, there are no large-scale reports of the use of thiazide diuretics in dogs with advanced heart failure.

Aim: This retrospective study evaluated the therapeutic effect of concomitant hydrochlorothiazide (HTCZ) with loop diuretics in dogs with heart failure.

Methods: The study included 14 dogs diagnosed with advanced pulmonary edema with MI at two facilities. In all cases, high-dose loop diuretics (torsemide; 0.78 – 4 mg/kg/day) did not improve pulmonary edema. The results of the echocardiography and renal function tests before and after the administration of HTCZ (0.2–0.84 mg/kg/day) in addition to torsemide were statistically compared.

Results: The echocardiographic data demonstrated significant improvement in relation to cardiac stress; left atrium to the aorta ratio, normalized left ventricular internal dimension in diastole, and E wave velocity (m/s) after HTCZ administration. However, blood urea nitrogen and creatinine levels increased, and potassium levels decreased, indicating a decline in renal function following HTCZ administration.

Conclusion: This study suggests that the administration of HTCZ in combination with loop diuretics may be beneficial during advanced heart failure due to MI in dogs. The results can also be extended to patients who are resistant to loop diuretics, resulting in the improvement of cardiac function. However, as the combination of HTCZ and loop diuretics can deteriorate renal function, caution should be exercised prior to making recommendations regarding its use, and renal function should be monitored.

Keywords: Echocardiology, Hydrochlorothiazide, Loop diuretic, Mitral insufficiency, Pulmonary edema.

Cite this paper:

Iwanaga, K., Araki, R. and Isaka, M. 2021. A retrospective study of 14 dogs with advanced heart failure treated with loop diuretics and hydrochlorothiazide. Open Vet. J. 11(3), 342-345.