Retrospective Evaluation of Sildenafil Citrate as a Therapy for Pulmonary Hypertension in Dogs

• Published in: Journal of veterinary internal medicine Vol. 20; no. 5; pp. 1132 - 1135
• Main Authors: Bach, Jonathan F., Rozanski, Elizabeth A., MacGregor, John, Betkowski, Jean M., Rush, John E.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-09-2006
• Subjects: Animals; Collapse; Cor pulmonale; Dog Diseases - drug therapy; Dogs; Female; Hypertension, Pulmonary - drug therapy; Hypertension, Pulmonary - pathology; Hypertension, Pulmonary - veterinary; Hypoxemia; Male; Phosphodiesterase Inhibitors - therapeutic use; Piperazines - therapeutic use; Pulmonary arterial pressure; Purines; Retrospective Studies; Sildenafil Citrate; Sulfones; Syncope; Vasodilator Agents - therapeutic use; Viagra
• ISSN: 0891-6640; 1939-1676
• DOI: 10.1111/j.1939-1676.2006.tb00711.x

Pulmonary arterial hypertension (PH) is a pathologic condition in dogs characterized by abnormally high pressures in the pulmonary circulation and has been associated with a poor outcome. Sildenafil is a type V phosphodiesterase inhibitor that produces nitric oxide‐mediated vasodilatation. Sildenafil treatment decreases pulmonary arterial pressure and pulmonary vascular resistance in people with PH. The purpose of this study was to describe the clinical characteristics and outcome of dogs with PH treated with sildenafil. The cardiology database was searched for dogs with PH treated with sildenafil. PH was defined as systolic pulmonary arterial pressure (PAPS) 25 mmHg at rest. Medical records were reviewed for the following information: signalment, duration and type of clinical signs before treatment, underlying disease, estimated or measured PAPS, dosage and dosing interval of sildenafil, and the effect of treatment on clinical signs and pulmonary arterial pressure and survival time. Thirteen affected dogs were identified. Clinical signs included collapse, syncope, respiratory distress, and cough. Duration of clinical signs before presentation ranged from 3 days to 5 months. An underlying cause was identified in 8 dogs. The median sildenafil dosage was 1.9 mg/kg. Ten dogs received concurrent medications. Median PAPS was 90 mmHg; 8 dogs were reevaluated after therapy, and the median decrease in PAPS was 16.5 mmHg. The median survival time of all dogs was 91 days. Sildenafil appeared to be well tolerated in dogs with PH and was associated with decreased PAPS and amelioration of clinical signs in most. Sildenafil represents a reasonable treatment option for dogs with pulmonary hypertension.