Carbamazepine-erythromycin interaction. Case studies and clinical significance
B. A. Wroblewski, W. D. Singer and J. Whyte
Because of significant and seemingly haphazard fluctuations in serum
carbamazepine concentrations, we decided to investigate the possible link
between erythromycin administration and potential changes in serum
carbamazepine concentration. We studied four cases involving this
combination. In every case, serum carbamazepine concentrations either rose
dramatically (doubled or tripled previous steady-state concentrations) or
dropped precipitously once erythromycin therapy was discontinued. In all
cases, we report serum carbamazepine concentrations obtained before,
during, and after concurrent erythromycin administration. We conclude that
the combination of erythromycin and carbamazepine represents a clinically
significant drug interaction and should be avoided where possible.
