Effect of probenecid on the blood levels and urinary excretion of cefamandole.

Two oral 0.5-g doses of probenecid given 7 and 1 h before a single 1-g intramuscular dose of cefamandole resulted in higher serum levels of cefamandole than when cefamandole was given alone: 37 versus 20 mug per ml of serum, respectively. Cefamandole was not measurable (<0.3 mug/ml) at 8 h when it was given alone, whereas an average 8-h value of 2.9 mug/ml was obtained after pretreatment with probenecid. By prolonging the duration of these high cefamandole levels, probenecid should permit the treatment of more serious clinical infections, including those due to relatively resistant organisms, or permit a reduction in either the dosage of cefamandole or the frequency of administration.