Glyceryl trinitrate ointment
BMJ Group Medical Reference
Glyceryl trinitrate (GTN) ointment can help to heal anal tears in some people.  Doctors usually advise trying this treatment first. But some research has shown that tears have a tendency to come back after you stop treatment, in about half the people who use GTN.   
One summary of the research (a systematic review) looked at 15 studies on treatment with GTN for anal tears. The summary found that anal tears healed in: 
About 50 in 100 people who used GTN
About 40 in 100 people who didn't use GTN, but were advised to take warm baths, eat more fibre, and use laxatives if they needed to.
Another study showed that Botox injections might work better than GTN. 
GTN (brand name Rectogesic) helps to widen your blood vessels. This improves the blood flow to your anus. GTN comes as an ointment that you rub on your anus. It also comes as patches that you put on your skin. GTN patches are usually used to treat angina ( heart pain), but they may work well for anal tears too. You'll need a prescription from your doctor to get GTN ointment or GTN patches.
GTN causes headaches in about 25 in 100 people. 
Angina is the name that doctors use for a pain in your chest that you get when your heart muscle isn't getting enough oxygen.
The anus, which is at the end of the rectum, is where stools leave your body when you go to the toilet. Part of the anus is a muscle that helps you hold in the stool until you are on the toilet.
A systematic review is a thorough look through published research on a particular topic. Only studies that have been carried out to a high standard are included. A systematic review may or may not include a meta-analysis, which is when the results from individual studies are put together.
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