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Nifedipine and diltiazem are calcium channel blockers. They are usually taken as pills to lower blood pressure. But these medicines can also help heal anal fissures.

A gel form of these medicines is best. When used as a gel directly on the anus, these medicines work as well as nitroglycerin cream. ¹ The gel form of these medicines also has fewer side effects than the pill form.

One cause of fissures is increased tension (called resting pressure) and spasm in the internal anal sphincter, one of two muscles that control the anus. These medicines work by relaxing the smooth muscle, allowing the fissure to heal.