Side Effects of Topical Diltiazem for Anal Fissures
Topical 2% diltiazem cream is remarkably well-tolerated, with approximately 80% of patients reporting no adverse effects, making it significantly safer than alternative treatments like nitroglycerin. 1
Common Side Effects
Perianal Dermatitis and Itching
- Perianal itching is the most frequently reported side effect, occurring in approximately 10% of patients, but rarely leads to treatment discontinuation. 2, 3
- Perianal dermatitis may develop in a small subset of patients (approximately 5-6%), though most continue treatment despite this complaint. 3
Systemic Side Effects (Rare)
- Headaches occur in less than 3% of patients using topical diltiazem, which is dramatically lower than the frequent headaches seen with nitroglycerin therapy. 2, 3
- One case report documented drowsiness and mood swings occurring six weeks into treatment, leading to discontinuation. 2
- Systemic absorption is minimal with topical application, and no significant blood pressure changes have been documented in clinical trials. 4
Comparison with Oral Diltiazem
Topical diltiazem has a vastly superior safety profile compared to oral administration:
- Oral diltiazem causes side effects in 33% of patients, including rash, headaches, nausea/vomiting, and altered smell/taste. 4
- Topical formulation avoids systemic side effects entirely while maintaining therapeutic efficacy. 4
Impact on Treatment Compliance
- Side effects attributed to topical diltiazem rarely reduce compliance, with most patients able to complete the full 8-week treatment course. 1
- The low side effect burden makes diltiazem preferable to nitroglycerin, which causes treatment-limiting headaches in many patients. 5
Clinical Caveat
While adverse effects are uncommon, patients should be counseled that 59% may require additional treatment (medical or surgical) over a 2-year follow-up period, as diltiazem does not guarantee permanent cure. 1 This reflects the natural history of chronic anal fissures rather than a side effect of the medication itself.