Application of sildenafil for pulmonary hypertension in canines and foals

Pulmonary arterial hypertension is the most commonly recognized form of pulmonary hypertension in canines. Persistent pulmonary hypertension is a life-threatening condition in neonatal foals. Treatment of pulmonary hypertension in both canines and neonatal foals has focused on the correction of hypoxia and acidosis, not on the pulmonary hypertension itself. Identification of pulmonary hypertension in canines and foals has been made easier with the new diagnostic technologies that are being employed by veterinarians. Although retrospective reviews and studies have been published on the use of sildenafil, which is used primarily for the treatment of human erectile dysfunction, to treat pulmonary hypertension in human neonates, and the pharmacodynamics of sildenafil have been examined in various species, sildenafil has not been used widely in dogs or foals. Therefore, the adverse effects of sildenafil in canines and foals have not been determined. Until the stability of sildenafil in suspension has been determined, it is recommended that dose-specific capsules be prepared by compounding pharmacists utilizing lactose as a diluent and that veterinarians be encouraged to prescribe small quantities of capsules until a maintenance dose has been achieved.