EFFECT OF ANTITUMOR DRUGS ON SERUM LEVELS OF CEPHALOTHIN (CET) AND CEPHALORIDINE (CER)

Abstract

The effect of administration of antitumor drugs on serum levels of CET and CER was examined by both filter-paper disc agar diffusion method and cup plate method.
When antitumor drugs having both antitumor and antibacterial activity, such as MMC and DM, were combined with either CET or CER, synergism was observed.
In combinations of antimetabolic drugs, such as CA and 6 MP-R, with either CET or CER, the combined effect was either independent or antagonistic. For instance, independent action was seen in CA plus CET or CER, and in 6 MP-R plus CET, and antagonistic action was seen in 6 MP-R plus CER.
6 MP, another antimetabolite, in combination with CET or CER showed a synergistic action when tested by the filter-paper disc agar diffusion method, thus suggesting the presence of a low-grade antibacterial activity against Bacillius subtilis ATCC 6633.
The serum level of CER seems to be more strongly influenced by antitumor drugs than does that of CET. On the basis of the results obtained here, caution should be paid in the interpretation of serum levels of CET and CER when antitumor drugs are used simultaneously.