There are reports of damage from one dose of these drugs.

Stephen Fried wrote a book about fluoroquinolone damage. His wife has permanent epilepsy from one dose of Floxin (given to her for a urinary tract infection). (this is the parent molecule that Levaquin is derived from).

The book is called Bitter Pills.
Oprah's TV producer had a problem with it too. I saw that show that she did on drug reactions many years ago.

http://www.stephenfried.com/bitter-pills/

I bought and read this book when it came out. It was and still is an eye opener!

There at one time were many fluoroquinolone drugs, but some of them turned out to be very toxic and have been removed from the market. Omniflox lasted about 2 weeks on the shelves.
Tequin was removed from sale in 2008. Many of the me-too fluoroquinolones are gone today, due to toxicity.

This lists more that were removed from sale.
http://en.wikipedia.org/wiki/Adverse...uoroquinolones
and explains the risks in more detail.

Cipro has been the least toxic (but that is a relative statement), however during that anthrax scare after 9/11, Dr. Cohen was one doctor who got Cipro cancelled as a first line drug for exposure. There was a panic for it for short while and people taking it for "nothing" really, and getting exposed to the tendon damage and neurotoxicity etc.