Sildenafil is a phosphodiesterase-5 inhibitor that enhances tissue blood flow via vascular smooth muscle relaxation and stimulates nitric oxide release, which is beneficial for wound healing. Topical sildenafil is safe, nontoxic, and nonirritating for treatment of wounds in various noncanine species.1,2
This study evaluated the effect of a novel topical sildenafil citrate hydrogel on wound healing in dogs. Six dogs with 4 excision wounds each along the dorsum were administered a hydrogel containing 0%, 5%, or 10% sildenafil or a nonadherent bandage every 24 hours for 21 days. Daily topical sildenafil resulted in systemic concentrations that may have been in the therapeutic range for pulmonary hypertension in 3 dogs (1 dog at day 14 and 2 dogs at day 21), but plasma concentrations remained within safe ranges. Topical sildenafil promoted early granulation formation; however, additional research is needed to determine the most effective hydrogel formulation, as well as ideal timing and frequency of application.