How Nitroglycerin Ointment Helps Hemorrhoids
Nitroglycerin ointment relieves hemorrhoid pain by decreasing anal sphincter tone, which reduces pressure and spasm in the anal canal. 1
Mechanism of Action
Nitroglycerin works through smooth muscle relaxation:
- Reduces resting anal canal pressure: The primary therapeutic effect comes from relaxing the internal anal sphincter, which lowers the elevated resting pressures commonly associated with symptomatic hemorrhoids 2
- Decreases sphincter spasm: By reducing anal tone, nitroglycerin alleviates the painful spasm that contributes significantly to hemorrhoid discomfort 1
- Improves blood flow: The vasodilatory effect may enhance local perfusion to the affected area
Clinical Evidence
The American Gastroenterological Association guidelines note that nitroglycerin ointment relieved pain in thrombosed external hemorrhoids in prospective series, specifically through its anal tone-reducing properties 1.
For early-grade hemorrhoids with high anal pressures, a study demonstrated that 0.2% glyceryl trinitrate (nitroglycerin) ointment:
- Reduced maximum resting anal canal pressure from 115.0 mmHg to 94.7 mmHg (p<0.001) 2
- Significantly improved rectal bleeding, anal pain, throbbing, pruritus, irritation, and difficulty with bowel movements 2
- Provided sustained benefit even 14 days after stopping treatment 2
Specific Clinical Application
Best used for:
- Thrombosed external hemorrhoids (acute pain relief)
- First- or second-degree hemorrhoids with elevated resting anal pressures (>70 mmHg)
- Symptomatic hemorrhoids when medical therapy alone has failed
Dosing: Apply 0.2% nitroglycerin ointment topically to the perianal area three times daily 2
Important Caveats
Headache is the major limiting side effect, occurring in approximately 43% of patients 2. This is dose-dependent and may require discontinuation in some cases.
Nitroglycerin is NOT FDA-approved for hemorrhoid treatment - the FDA labeling only covers angina prophylaxis 3. This represents off-label use, though it has guideline support for specific hemorrhoid presentations.
Limited role compared to other treatments: The AGA guidelines emphasize that data supporting topical agents for hemorrhoids are generally lacking, and nitroglycerin is specifically mentioned only for thrombosed external hemorrhoids 1. For most hemorrhoid grades, fiber supplementation, rubber band ligation, or surgical options remain the primary evidence-based treatments.