Erythromycin-carbamazepine interaction

Inhibition by erythromycin of the conversion of carbamazepine to its active 10,11‐epoxide metabolite.

“…While the only other study examining the effect of erythromycin on the single dose kinetics of CBZ (Wong et al, 1983) produced results very similar to ours, i.e. only a moderate decrease in CBZ clearance, several reports indicate that in chronically CBZ-treated patients erythromycin can cause an up to 100-200% increase in plasma CBZ levels (Berrettini, 1986;Carranco et al, 1985;Hedrick et al, 1983;Jaster & Abbas, 1986;Vaida et al, 1984;Wroblewski et al, 1986). From the clinical point of view, our data suggest that the manifestations of toxicity observed when the two drugs are combined can be ascribed virtually entirely to unchanged CBZ.…”

“…Carbamazepine absorption was not apparently affected by erythromycin, peak serum As shown in Figure 1, there is a clear discrepancy between the erythromycin-induced changes in CBZ kinetics, which were relatively small, (Berrettini, 1986;Carranco et al, 1985;Hedrick et al, 1983;Jaster & Abbas, 1986;Vaida et al, 1984;Wroblewski et al, 1986). From the clinical point of view, our data suggest that the manifestations of toxicity observed when the two drugs are combined can be ascribed virtually entirely to unchanged CBZ.…”

“…Administration of erythromycin to carbamazepine (CBZ)-treated patients can increase serum CBZ levels and precipitate clinical signs of CBZ intoxication (Berrettini, 1986;Carranco et al, 1985;Goulden et al, 1985;Hedrick et al, 1983;Jaster & Abbas, 1986;Mesdjian et al, 1980;Vaida & Bladin, 1984;Wroblewski et al, 1986). Although this interaction is generally considered to be due to inhibition of CBZ metabolism (Wong et al, 1983), no metabolite measurements have been made to support such an hypothesis.…”