Management of anal fissure
Management of an acute anal fissure is conservative. Advise patients to avoid hard stools (by using stool-softening or bulk-forming laxatives; see Functional constipation in adults for dosages) and use warm salt baths after bowel movementsStewart, 2017.
Over-the-counter topical preparations containing a local anaesthetic may help to relieve pain or discomfort associated with acute anal fissures. However, prolonged use should be avoided because they can cause adverse effects such as local skin sensitisation or dermatitisJensen, 1986Stewart, 2017.
Anal fissure can be perpetuated by internal anal sphincter spasm, which impairs perfusion and healing. Therefore, topical medications that reduce internal anal sphincter spasm may be useful. If symptoms persist despite the above therapy, use:
glyceryl trinitrate 0.2% ointment 1 to 1.5 cm topically using a gloved finger inserted gently into the anal canal, 3 to 4 times daily. glyceryl trinitrate glyceryl trinitrate glyceryl trinitrate
Systemic absorption of glyceryl trinitrate may cause headache or hypotension. Due to the risk of profound hypotension, topical glyceryl trinitrate should not be used if the patient has taken a phosphodiesterase inhibitor (eg sildenafil) in the last 24 hours.
An alternative is a topical preparation containing a calcium channel antagonist (either diltiazem 2% or nifedipine 0.5%)1Boland, 2020Stewart, 2017.
Management of chronic anal fissure requires specialist advice. Surgery (most commonly lateral sphincterotomy) is often required for healing, but is associated with a small risk of faecal incontinenceStewart, 2017. Local injection of botulinum toxin may be used in some patients; repeat treatment is often requiredStewart, 2017.