Antibiotic of the penicillin family that is resistant to penicillinase, the penicillin-destroying enzyme released by some bacteria, especially staphylococci. It is used to treat severe infections caused by penicillinase-producing staphylococci. Adverse effects include allergic reactions and gastrointestinal disturbances.
An antibiotic used to treat infections caused by a wide variety of bacteria. It is administered by mouth or injection; side-effects include allergic reactions and digestive upsets.