Alterations in cefalosporin levels in the serum and mandible of hyperlipaedemic rats after co-administration of ibuprofen.

Several interactions between antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) have been described in the literature, and it has been reported that hyperlipidaemia induces significant changes in cefalosporin levels. The aim of this study was to determine the changes in the levels of several cefalosporins in the serum and mandible after ibuprofen co-administration in hyperlipaedemic rats. One hundred and forty male Wistar rats were used and divided in 4 groups (A-D), each of which was further divided into 5 subgroups (1-5), either with placebo or with various treatment regimes. The co-administration of NSAIDs led to increased cefalosporin levels in both control and hyperlipidaemic animals. Hyperlipidaemia was also found to augment cefalosporin levels. These observed increases might be due to the displacement of the cephalosporins from their binding sites in serum albumin and tissue proteins in the presence of ibuprofen. NSAIDs showed a greater binding affinity for tissue proteins compared to the cephalosporins, and probably play an antagonistic role in protein binding, resulting in higher concentrations of antibiotics.