Nitrogesic Rectal Ointment is a medicine used for relieving the pain associated with anal fissures (tear in the lining of the anus). It improves blood flow and reduces the pressure in anal tissues. Nitrogesic Rectal Ointment promotes healing of fissures and provides pain relief. It is for external use only. It is advised to use it in the dose and duration as advised by your doctor. Clean and dry the affected area and gently apply it over the affected area. The common side effects of this medicine include headache, dizziness, and nausea. You may also experience slight anal irritation upon application of the medicine. This is temporary and usually resolves on its own in some time. You should consult your doctor if it does not resolve or persists for a longer duration. Do not use the medicine if you are taking medicines to treat high blood pressure in your lungs (pulmonary hypertension), or if you have anemia or glaucoma (increased pressure inside the eye). Always tell your doctor what other health conditions you have and what other medicines you are taking. If you are pregnant, thinking about becoming pregnant, or breastfeeding, ask your doctor before taking this medicine.