Nitrofurantoin
"Was prescribed this medication for my UTI.  After taking my second pill, I started experiencing severe migraines and blurred vision. It was so bad that I couldn't drive. I stopped taking it yesterday and my vision is still not 100%. I recommend people try this for a day and observe your bodies reaction. Lots of people have a bad reaction to this medication (Ive NEVER had a reaction to medication in my life only this one). If your sensitive to certain medication I highly recommend you don't take this one."