Pharmacokinetics of cephradine given intravenously with and without probenecid.

1 In the light of questions raised by an earlier oral study (Welling, Dean, Selen, Kendall & Wise, 1979) the influence of probenecid on the pharmacokinetics of intravenously administered cephradine has been investigated. 2 Intravenous administration of cephradine resulted in a bi-exponential curve and the level of antibiotic after 15 min was significantly greater when subjects received probenecid than when they did not. The influence of probenecid on urinary excretion of cephradine was similar to that observed previously. 3 The increase in serum of cephradine due to probenecid could be accounted for by the decrease in the elimination rate of the antibiotic. These results are discussed in the light of other observations.