Your doctor may prescribe the following medicines to relieve the spasm of an anal fissure: local anesthetic e. g. lidocaine- this may come as a cream, ointment or suppository and will completely block pain from the anus; Glyceryl trinitrate- a rectal ointment that will relax the internal anal sphincter muscle. This will reduce the spasm and improve the blood flow to your anus and help the fissure heal; Calcium channel blockers e. g. diltiazem and nifedipine- these medicines act by relaxing part of the sphincter to reduce the spasm and the pressure in your anus. Studies of these treatments have produced mixed results so you should ask your doctor for advice.
Attribution: BUPA