I know lots of people use Tinidazole in place of Flagyl...same med basically, just easier than Flagyl to tolerate I believe...but I have never heard of anyone being on Tini IV...good question.
You can get Flagyl in IV though...I know this since I was on it for a time.
I've seen this in foreign source descriptions, but not U.S.A. drug descriptions, although it might exist.
Check France, Mexico, and South American countries.