Nitrofurantoin
"Very effective antibiotic--cleared symptoms within 24 hours. Side effects are terrible. You will feel like you have the stomach flu or food poisoning--fever, chills, and extreme nausea. I would recommend taking it with a big meal. I feel marginal (not wonderful) eating a big lunch and taking it, but eating a relatively small dinner and taking the pill 3 hours later, I spent the night thinking I had another illness besides the infection. Probably will ask for a different antibiotic if this happens again. Aside from slight nausea, I never react to medications, and this is all new to me."