Help! What does GTN & LIS stand for??

GTN = Glyceryl Trinitrate, which is an alternative name for the chemical Nitroglycerin (which helps relax your sphincter so that it can allow the fissure to heal). In my experience, Nitrofedipine is much better with less side effects (GTN can give you severe headaches).
LIS = Lateral Internal Sphincterotomy, which is a minor operation which can be carried out under either local or general anaesthesia. Basically, a scalpel is used to cut the internal sphincter which will lower the resting pressure of the sphincter without destroying the effect of the sphincter, allowing the fissure to heal.
I hope this helps.

Thank You so MUCH!!!
I am currently using "NIPEDIPINE"----I feel 99.9% better.
I had "LIS" surgery 25 years ago -- I've always called it a sphincterectomy. --Same thing?? Any how, my Dr. said after 25 years the "warranty" is up. I hope to heal it w/o surgery.Ointment seems to be doing the trick. FINGERS CROSSED!!!

No problem.
How are your bowel movements? Are you taking Miralax?

No Miralax but Bran & mineral oil---I eat a very high fiber diet & drink tons of water---I have MANY bowel movements a day---which is causing my problem. I'm trying to find the balance between having ONE comfortable BM & being constipated. Slightly cutting down on Bran & mineral oil.
I also take at least 2 sitz baths a day---I meditate & so far I've gotten better in just a few days---THANK GOD!!!