Meropenem, a new carbapenem antibiotic, is more active against gram-negative bacilli and less active against gram-positive cocci than is imipenem, and there are several important structural differences between meropenem and the older carbapenem. These differences may be responsible for the lower potential for the induction of epileptogenic activity observed with meropenem as well as for its increased stability to degradation by dehydropeptidase-I. The pharmacokinetics of meropenem are typical of those of a parenteral beta-lactam antibiotic with low protein binding and predominantly renal excretion. Dosage reduction is required in patients with reduced renal function; no dosage adjustment is required for patients with hepatic impairment. Meropenem has excellent penetration in abdominal tissues, bile, blister fluid, inflammatory exudate, cerebrospinal fluid (in the presence of inflammation), gynecologic tissues, respiratory tract tissues, and urinary tract tissues; tissue levels are generally equal to or above the levels needed for the treatment of patients with susceptible pathogens.