Adverse effects of newer cephalosporins. An update.

While classifications into generations according to antimicrobial activity has helped clinicians incorporate the increasing number of cephalosporins into their pharmacological repertoire, adverse effects among the different agents fail to follow similar categories. In general, cephalosporins are fairly well tolerated antibiotics, and toxicity has been limited to specific agents. Subtle differences in chemical structure and pharmacokinetics can influence the potential for adverse effects. The route of administration may result in minor adverse reactions, including thrombophlebitis and pain. The most common adverse effects of cephalosporins are allergic reactions, occurring in 0.9 to 3.2% of patients. Cephalosporins have very rarely been associated with haematological toxicity (less than 1% of patients), but specific agents have been associated with neutropenia, hypoprothrombinaemia, haemolytic anaemia, and problems with platelet production and function. Other reactions include localised gastrointestinal disturbances, hepatotoxicity (e.g. biliary sludging), nephrotoxicity and mild central nervous system effects. The cephalosporins are generally well tolerated in the paediatric population. Very few interactions have been observed between cephalosporins and other drugs, largely because cephalosporins do not affect the microsomal P450 hepatic enzyme system. While cephalosporins are considered to be relatively 'safe' drugs, the introduction of newer members warrants continued careful observation for reporting of adverse drug reactions.