Ciprofloxacin
"Am currently taking Cipro to deal with a UTI.  Had one about a month ago, took Cipro, it seemed to go away, but now it's back with a vengeance.  But I'm taking it with great reluctance. It use to be my ENT's go-to drug for sinus infections, which I would typically get twice a year (allergy induced).  Then, about 4 years after first taking the drug, I woke up one morning and my right foot totally collapsed due to tendon rupture.  Zero arch.  At the time (1990) there weren't any tendon warnings with the drug and no one  could explain how tendons could rupture overnight.  Now my podiatrist attributes the event to the Cipro.  I have to wear a Richie brace on that foot/ankle."