Topical nitroglycerin therapy for anal fissures and ulcers

To the Editor: Myenteric nerves innervating the internal sphincter muscle of the anus produce and release nitric oxide,¹,² the chemical messenger that mediates relaxation of this muscle.¹ A derangement in nitric oxide regulation may underlie the anal-sphincter hypertonicity associated with anal fissures and ulcers. Nitroglycerin, which is locally metabolized to nitric oxide, lowers the mean resting pressure of the anal sphincter when applied topically to the anus.³ A pilot study of 15 patients showed that topical nitroglycerin was useful in treating anal fissures and ulcers.⁴ Forty patients with anal fissures (26 women and 14 men; mean age, 38 years).