It is anti-inflammatory that as far as I know can have nasty side-effects as any strong anti-inflammatory of that kind. There is also a "foam" form , I think :roll: .
Yes, it is mostly prescribed for very "hard-core" inflammations in the intestinal tract and also in severe cases of proctitis (inflammation of the anal area ) or rectum.
I was once prescribed that medication but decided not to use it after I read original manufacturer's drug description, interaction and whole list of side-effects. One of them was inflammation of the pancreas (if I remember it correctly- you can Google the drug on-line ) and I decided that I would rather have my butt inflamed

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My personal opinion is that that drug is really overkill in the simple case of hemorrhoids and fissures (when I say simple, I think about fissures NOT caused by Chrnon's or similar serious inflammatory processes).
I hope that it was not the first-line therapy your doctor prescribed

... I am not regular on this forum so I do not know your whole story :roll: . I hope you will heal fast and if I were you I would definitely not stay too long on Canasa if there is no ulceration present !!!
Best of luck

and may you heal fast and completely !!!