A Retrospective Study of Sildenafil Administration in 55 Cats with Cardiopulmonary Disease (2009–2021)

Sildenafil is a drug used to successfully manage a variety of cardiopulmonary disorders in people and dogs, but there is limited information on its use in cats. The objective was to review the medical records of cats that received sildenafil as part of their clinical management. Medical records and pharmacy databases were searched for cats that received sildenafil for ≥24 h between 2009 and 2021, and data were collected from medical records. Fifty-five cats received sildenafil for ≥24 h and were included in the study: 43 with primary cardiac disease (acquired, n = 28; congenital, n = 15) and 12 with primary respiratory disease. Side effects possibly attributed to sildenafil were identified in two cats (systemic hypotension, n = 1; polydipsia, n = 1), and sildenafil was discontinued in the cat with hypotension. Sildenafil was discontinued in an additional three cats due to a lack of improvement in clinical signs. No cat was documented to develop worsening pulmonary edema within 72 h of starting sildenafil. Median duration of sildenafil administration was 87 days (range, 2–2362 days). Sildenafil administration in cats appeared to be generally well-tolerated. Studies are needed to determine whether sildenafil administration to cats with cardiopulmonary disease improves the quality of life or survival times.