Nitrofurantoin

Nitrofurantoin, sold under the trade name Macrobid among others, is an antibiotic used to treat bladder infections. It is not effective for kidney infections. It is taken by mouth.

Common side effects include nausea, loss of appetite, diarrhea, and headaches. Rarely numbness, lung problems, or liver problems may occur. It should not be used in people with kidney problems. While it looks like it is generally safe during pregnancy it should not be used near delivery. It works by slowing growth rather than killing bacteria.