Cipro Warning: Stay Away!
I've had a couple questions lately about ciprofloxacin (also called "cipro"), so I thought it might be a good time to make a few comments about this drug. Cipro is an antibiotic that is very useful in many species. Unfortunately, this does not include horses.
I am aware of only two published papers about the use of cipro in horses (other than topically on the eyes). The first was a study that showed when you give cipro orally to ponies, they don't absorb it well enough from their intestines to reach therapeutic levels in the rest of the body. Therefore, the drug won't work effectively against any bacterial infection in the rest of the body. The other paper described a series of four horses that developed severe (and sometimes fatal) diarrhea after being treated with cipro. So, if the drug isn't absorbed well enough to kill any bacteria in the horse's body, but it can still kill bacteria in the intestinal tract and cause fatal diarrhea, we really shouldn't be using it. Sounds logical enough.
Yet it seems that cipro is still being used in horses. I've heard that lower doses are being used because they are less likely to cause diarrhea. That's probably true, but if higher doses couldn't produce levels of the drug that would kill bacteria in the body tissues, then lower doses certainly won't. While the risk of diarrhea may be lower with lower doses, the chances of having any desirable effect on an infection are probably close to zero. Horses that get better while being treated with cipro probably didn't really need an antibiotic in the first place - they are getting better in spite of being treated with cipro, not because of it.
Antibiotics are important and sometimes life-saving drugs, but treatment always comes with some degree of risk, no matter which drug is chosen. However, there are still many effective antibiotics that, over time, have been shown to be lower risk than others. We should stick with these as much as possible, and not resort to a drug like ciprofloxacin that, based on current evidence, is likely to do more harm than good.
