Is taking Ciprofloxacin actually dangerous?

I was just prescribed some for a UTI, but so far I've only taken one 500mg pill. I was doing some research about it online and it's likely to cause severe tendon damage, and that it is NOT recommended as a first-line antibiotic for a urinary tract infection. My doctor is kind of an idiot anyway (she's the type that will let you bring the diagnosis while she supplies the pills- no thinking involved on her part) but is it common knowledge that Cipro is not recommended, or am I just being a hypochondriac?