Ampicillin is an antibiotic that works by disrupting the formation of the bacterial cell wall during growth, according to Drugs.com. This makes the cell wall weak and causes it to break, killing the bacteria.
Ampicillin treats a variety of bacterial infections, including pneumonia, bronchitis, and infections involving the skin, ears, lungs and urinary tract, states MedlinePlus. It is available in capsules, liquid and pediatric drops. Ampicillin is generally taken every six hours, at least one hour before or two hours after a meal.
It is important for patients with a history of kidney, liver or blood disease; allergies; asthma; hay fever; or colitis and other stomach problems to notify their doctor before taking ampicillin, according to MedlinePlus. Patients are also advised to tell their doctor about other medications they are taking, especially blood thinners, birth control pills, vitamins and other antibiotics, as these medications sometimes interact with ampicillin.
Potential side effects of ampicillin include vomiting, diarrhea, upset stomach and mild skin rash, states MedlinePlus. Reporting these side effects to a doctor is recommended only if they are severe or unrelieved. Serious side effects that warrant an immediate call to a doctor include severe skin rash, itching, hives, wheezing and problems breathing or swallowing.