<P> The most common side effects with nitrofurantoin are nausea, headache, and flatulence . Less common adverse events (occurring in less than 1% of those taking the drug) include: </P> <Ul> <Li> Gastrointestinal: diarrhea, dyspepsia, abdominal pain, constipation, emesis </Li> <Li> Neurologic: dizziness, drowsiness, amblyopia </Li> <Li> Respiratory: acute pulmonary hypersensitivity reaction </Li> <Li> Allergic: pruritus, urticaria </Li> <Li> Dermatologic: hair loss </Li> <Li> Miscellaneous: fever, chills, malaise </Li> </Ul> <Li> Gastrointestinal: diarrhea, dyspepsia, abdominal pain, constipation, emesis </Li> <Li> Neurologic: dizziness, drowsiness, amblyopia </Li>

What types of antibiotics concentrate in the urine