GTN 0.4% Rectal Ointment

How should I use GTN Ointment?

• Apply a small amount (pea-sized) to the affected area every 12 hours.
• Wash hands before and after application.
• Insert a fingertip or use an applicator if directed.
• Do not exceed the prescribed amount.
• Continue for up to 8 weeks or as advised by your doctor.

What are the possible side effects?

• Very common: headaches (usually improve over time).
• Common: dizziness, light-headedness, or local irritation.
• Rare: fainting or drop in blood pressure, especially when standing quickly.

Avoid driving or operating machinery if you feel dizzy. Consult your doctor if side effects persist or worsen.

What ingredients are in GTN Ointment?

• Active ingredient: Glyceryl trinitrate 0.4%
• Other ingredients: Propylene glycol, lanolin, white soft paraffin, and other excipients.

How should GTN Ointment be stored?

• Store below 25°C in a dry place.
• Keep the tube tightly closed when not in use.
• Keep out of sight and reach of children.
• Do not use after the expiry date shown on the packaging.

What is GTN 0.4% Rectal Ointment?

GTN 0.4% Rectal Ointment, containing glyceryl trinitrate as its active ingredient, is a prescription-only medicine used for the treatment of chronic anal fissures. Anal fissures are small tears in the skin lining the anal canal, often caused by constipation, straining during bowel movements, or trauma. These tears can be extremely painful and may bleed, especially during or after passing stools.

GTN ointment works by relaxing the smooth muscles in the anal area, particularly the internal anal sphincter. This relaxation reduces anal pressure and increases blood flow to the fissure site, supporting the body’s natural healing process. The increase in blood supply is vital because anal fissures often heal poorly due to restricted blood circulation in the area. By improving circulation and reducing strain, GTN helps promote faster and more complete healing.

The ointment is typically supplied in a 30g tube at a concentration of 0.4%, which is considered the standard strength for treating this condition. It should be applied either externally around the anus or internally just inside the anal canal. Patients may use a clean fingertip or a suitable applicator to apply a pea-sized amount of ointment, usually twice daily or as directed by a healthcare provider.

Many people experience pain relief within the first few days of use, though it’s important to continue treatment for up to 8 weeks or as prescribed to ensure full healing. Patients are advised to follow a fibre-rich diet and drink plenty of fluids during treatment to reduce the risk of further irritation caused by constipation.

The most common side effect of GTN ointment is headache, which occurs due to its vasodilating action. This side effect is generally mild and tends to lessen over time. Other possible side effects include dizziness or light-headedness, especially when standing up too quickly.

GTN ointment should not be used with certain medications, such as phosphodiesterase inhibitors (e.g. sildenafil for erectile dysfunction), due to the potential for serious drops in blood pressure. Always inform your doctor of all medications you are taking before beginning GTN treatment.

With correct use and supportive care, GTN 0.4% Rectal Ointment offers a proven and effective way to manage the pain and promote healing of chronic anal fissures.