1. Ampicillin is prescribed to people diagnosed with various infections, including urinary tract infections, genital infections and respiratory infections. Your doctor can recommend taking this drug for a number of other conditions. Being allergic to penicillin or cephalosporin antibiotics can be a contraindication for taking ampicillin. If you experience a skin reaction, fever, diarrhea, shortness of breath and wheezing seek immediate medical help as these may be the symptoms of an allergic reaction. Seek emergency medical assistance if you suspect an allergic reaction.