From the Guidelines
Nitroglycerin ointment is not the preferred treatment option for anal fissures due to its lower healing rates and higher risk of side effects compared to other treatments, such as calcium channel blockers. According to the most recent and highest quality study 1, calcium channel blockers (CCBs) are more effective than glyceryl trinitrate (nitroglycerin) in healing anal fissures, with a healing rate ranging from 65 to 95%, and are associated with less risk of headache and hypotension. The use of nitroglycerin ointment is still an option, but it should be considered after weighing the potential benefits and risks, including the common side effects of headaches and dizziness. Some key points to consider when using nitroglycerin ointment for anal fissures include:
- Typical concentration: 0.2% to 0.4% applied to the anal canal 2-3 times daily for 6-8 weeks
- Standard regimen: placing a pea-sized amount just inside the anus using a finger or cotton swab
- Mechanism of action: relaxing the internal anal sphincter muscle through the release of nitric oxide, increasing blood flow to the area and reducing pain while promoting healing
- Common side effects: headaches in up to 40% of patients, dizziness or lightheadedness due to decreased blood pressure
- Contraindications: patients taking medications for erectile dysfunction such as sildenafil, tadalafil, or vardenafil due to dangerous hypotensive effects. However, based on the latest evidence 1, calcium channel blockers, such as diltiazem or nifedipine, are the preferred treatment option for anal fissures due to their higher healing rates and lower risk of side effects.
From the Research
Nitroglycerin for Anal Fissure
- Nitroglycerin ointment is used to treat chronic anal fissure pain by reducing increased anal canal pressure and improving anodermal blood flow 2.
- A study found that 0.4% nitroglycerin ointment significantly increased the rate of decrease in mean visual-analogue-scale pain scores compared to placebo in patients with chronic anal fissure pain 2.
- The most common adverse event associated with 0.4% nitroglycerin ointment is headache, which can be severe in 20-25% of patients 2.
Efficacy of Nitroglycerin
- Topical nitroglycerin has been shown to be effective in treating anal fissures, with a healing rate of 75% for chronic fissures and 83% for acute fissures in one study 3.
- However, the recurrence rate for chronic fissures at 9 months was 67% in the same study 3.
- Another study found that topical nitroglycerin was effective in 56% of acute fissures and 41% of chronic fissures, but with a high incidence of adverse reactions 4.
Comparison with Other Treatments
- A study compared the efficacy of topical nifedipine and diltiazem for the treatment of acute anal fissure, and found that nifedipine had a higher remission rate and earlier pain relief compared to diltiazem 5.
- However, the study did not compare the efficacy of nitroglycerin with nifedipine or diltiazem 5.
Pharmacotherapy
- Topical nitroglycerin ointment preparations have been studied as an alternative to surgery for the treatment of anal fissures, with some studies showing promising results 6.
- However, there is no consensus on the concentrations, compositions, and applications necessary to obtain good results with topical nitroglycerin 6.