Ampicillin should be stopped if a skin rash occurs. It should preferably not be given to patients with infectious mononucleosis since they are especially susceptible to ampicillin-induced skin rashes; patients with lymphatic leukemia or possibly HIV infection may also be at increased risk of developing skin rashes.
Careful administration: Patients with severe liver disorder.
Patients with moderate or severe renal disorder. (It should be administered at regular intervals because the blood concentration last.)
Patients with a history of hypersensitivity to penicillin or cephalosporins (cross tolerance).
Patients who or whose family have a predisposition to develop allergic reactions such as bronchial asthma, rash and urticaria.
Patients with poor oral intake or receiving parenteral nutrition or aged patients. (As vitamin K deficiency symptoms may appear, close observation should be made.)