How does diltiazem work for fissures? A guide to its mechanism and use

October 6, 2025 •

3 min read

According to the American Society of Colon and Rectal Surgeons, medical therapies like topical calcium channel blockers are the first-line treatment for chronic anal fissures, aimed at reducing spasms and promoting healing. Understanding how does diltiazem work for fissures provides crucial insight for patients seeking relief from this painful condition.

Quick Summary

Diltiazem works for fissures by acting as a topical calcium channel blocker to relax the internal anal sphincter, decreasing pressure and increasing blood flow to aid healing. It offers a well-tolerated, non-surgical approach to treating this painful condition.

Key Points

Relaxation of the Anal Sphincter: Diltiazem, a calcium channel blocker, relaxes the internal anal sphincter muscle, which helps to reduce the high resting pressure often associated with anal fissures.
Improved Blood Flow: The muscle relaxation leads to improved blood flow to the torn tissue, delivering essential nutrients and oxygen required for healing.
Pain and Spasm Reduction: By lowering the anal canal pressure and resolving muscle spasms, diltiazem helps diminish the pain experienced during and after bowel movements.
Topical Administration: It is most commonly used as a 2% cream or ointment, applied locally to the affected area for direct and concentrated action with minimal systemic absorption.
Lower Systemic Side Effects: Compared to alternative treatments like topical nitroglycerin, diltiazem has a lower incidence of systemic side effects, such as headaches, improving patient tolerability.
Promotes Long-Term Healing: A full course of treatment, typically 6-8 weeks, is crucial for complete healing and to minimize the chances of the fissure recurring.
Compounded Medication: Topical diltiazem is not a standard, FDA-approved product but is prepared by compounding pharmacies, sometimes with other ingredients like lidocaine for added pain relief.

Understanding the Vicious Cycle of Anal Fissures

An anal fissure is a small tear in the lining of the anus that often causes severe pain, bleeding, and muscle spasms. This pain, which is triggered by and can persist long after a bowel movement, often leads to a debilitating cycle. The discomfort causes the internal anal sphincter (a ring of muscle) to spasm and tighten involuntarily, increasing the resting pressure within the anal canal. This sphincter hypertonia is a key component of chronic fissures, as the increased pressure reduces blood flow to the already damaged tissue. The resulting localized ischemia (inadequate blood supply) impairs healing, perpetuating the cycle of pain and spasm. Medications designed to break this cycle are central to effective treatment.

The Pharmacological Role of Diltiazem

Diltiazem is a non-dihydropyridine calcium channel blocker (CCB). While widely known for its use in cardiovascular conditions like hypertension and angina, a topical formulation is used off-label to treat anal fissures.

How does diltiazem work for fissures? The mechanism is centered on its ability to block slow L-type calcium channels in smooth muscle cells, including those of the internal anal sphincter. Diltiazem inhibits the influx of calcium ions, which reduces muscle contraction and causes relaxation of the internal anal sphincter. This relaxation lowers the sphincter's resting pressure and improves blood flow to the anoderm, aiding in the healing process and reducing pain associated with spasms.

Administration and Treatment Regimen

Diltiazem for anal fissures is typically a compounded 2% cream or ointment. It is often formulated with other soothing ingredients, such as lidocaine for additional pain relief. The application involves applying a small amount just inside the anal verge, usually twice daily with a gloved finger. Treatment typically lasts for 6 to 8 weeks and should be used alongside other conservative measures like a high-fiber diet, increased fluids, and sitz baths.

Side Effects and Tolerability

Topical diltiazem generally has a lower incidence of systemic side effects compared to other medical therapies like topical nitroglycerin. Common side effects are usually local or mild and can include headaches, dizziness, or local irritation. The risk of side effects is generally low.

Diltiazem vs. Other Topical Treatments


Feature	Diltiazem	Nifedipine	Nitroglycerin (GTN)
Drug Class	Calcium Channel Blockers (CCB)	Calcium Channel Blockers (CCB)	Nitrate
Mechanism	Inhibits calcium influx to relax smooth muscle.	Inhibits calcium influx to relax smooth muscle.	Releases nitric oxide, causing vasodilation and smooth muscle relaxation.
Common Side Effects	Mild headaches, dizziness, local irritation.	Flushing, dizziness, mild headaches.	Frequent and potentially severe headaches, hypotension.
Efficacy	Effective, with healing rates comparable to GTN in some studies. Some evidence suggests lower efficacy than nifedipine.	High healing rates reported in some studies, with potentially faster pain relief than diltiazem.	Effective, but hindered by high rate of treatment-limiting headaches.
Recurrence Rate	Lower recurrence rates reported compared to GTN in some studies.	Recurrence rates similar to diltiazem.	Higher recurrence rate compared to CCBs.

Conclusion

Topical diltiazem effectively treats anal fissures by relaxing the internal anal sphincter, reducing pressure, and improving blood flow to promote healing. Its mechanism as a calcium channel blocker helps break the cycle of pain and spasm. Diltiazem is often preferred due to its favorable side effect profile compared to topical nitrates. As a compounded medication, it requires a prescription and should be used as directed, combined with supportive measures for optimal results and reduced recurrence.

For more information on the management of anorectal disorders, consult the ACG Clinical Guidelines.

Frequently Asked Questions

An anal fissure is a small tear or cut in the moist, thin tissue that lines the anal canal. It is often caused by trauma from constipation or diarrhea and leads to significant pain and bleeding.

Diltiazem heals fissures by relaxing the internal anal sphincter, reducing the high resting pressure that restricts blood flow. This improved circulation helps the torn tissue to heal more effectively.

While some systemic absorption can occur, especially in the early stages of treatment when the area is inflamed, the topical formulation of diltiazem has minimal systemic effects compared to oral versions. This is why topical side effects are generally mild and localized.

While pain relief may start relatively quickly, significant improvement and complete healing can take several weeks. A typical course of treatment lasts 6 to 8 weeks, and it is important to complete the full regimen.

Both medications reduce anal sphincter pressure to promote healing. However, diltiazem is associated with significantly fewer headaches and recurrences compared to nitroglycerin, making it a preferred first-line option for many patients.

Common side effects are typically mild and localized, including headaches, dizziness, and local irritation or burning at the application site.

Before using diltiazem with other medications, especially other topical treatments or drugs for blood pressure or heart conditions, you should consult your healthcare provider to avoid potential interactions.

Yes, topical diltiazem for fissures is a compounded medication that requires a prescription from a healthcare provider. It is not an over-the-counter product.