At a glance
Rectogesic is a brand name for GTN (glyceryl trinitrate) ointment — one of the most commonly prescribed topical treatments for anal fissures. It relaxes the internal sphincter muscle, improves blood flow, and supports healing. This guide covers the practical aspects of using it.
What it is
Rectogesic contains GTN as its active ingredient. GTN releases nitric oxide when applied to the skin, which relaxes smooth muscle. When applied to the anal margin, this relaxes the internal sphincter — the muscle whose spasm contributes to fissure persistence.
The ointment is applied externally, to the outside of the anal canal, not inserted deeply inside.
How to use it
The application routine
- Clean the area — a sitz bath or gentle wash is ideal
- Apply a small amount — typically pea-sized, using the dosing guide provided
- Apply to the anal margin — gently, using a gloved finger or finger cot
- Wash hands thoroughly — GTN can be absorbed through the skin of the fingers
- Repeat as prescribed — usually twice daily, morning and evening
Practical tips from people who use it
- Use a finger cot or disposable glove — this prevents GTN absorption through the fingers, which can cause headaches even from hand contact
- Apply after a sitz bath — the tissue is clean and warm, and the blood flow is already increased
- Lie down for a few minutes after applying — this reduces the chance of dizziness from the blood pressure-lowering effect
- Store as directed — Rectogesic has specific storage requirements noted on the packaging
- Set a reminder — consistency is important, and it is easy to forget an application when you are feeling better
Common side effects
Headaches
The most frequently reported side effect. GTN dilates blood vessels, including those in the head. Strategies people describe for managing headaches:
- Take paracetamol 20 to 30 minutes before applying
- Use the minimum amount recommended
- Apply while lying down
- Headaches typically lessen after the first week
Other effects
- Light-headedness or dizziness — particularly when standing up after application
- Flushing — a sensation of warmth
- Mild stinging at the application site — usually brief
When to contact your doctor
- Severe headaches that are not managed with painkillers
- Fainting or persistent dizziness
- Severe skin reaction at the application site
- Side effects that are intolerable and preventing you from completing the course
What to expect
Rectogesic does not provide instant relief. The typical pattern:
- Days 1 to 7: Side effects are most noticeable. Some people begin to notice reduced fissure pain. Others notice no change yet.
- Weeks 2 to 4: Gradual improvement in pain, particularly after bowel movements. Headaches often lessen.
- Weeks 4 to 8: Continued healing. The full course is important even if you feel better.
- After the course: The fissure may have healed. If not, your clinician will discuss alternatives.
Alongside other care
Rectogesic addresses the sphincter spasm component of fissure persistence. It works best alongside:
- Stool management (fibre, hydration, stool softeners)
- Sitz baths (particularly before application)
- Dietary adjustments
- Good toilet habits (not straining, not rushing)
The ointment creates an environment for healing. The other measures prevent re-injury.