Vinca alkaloids Clarithromycin

CLARITHROMYCIN, ERYTHROMYCIN VINCA ALKALOIDS -VINBLASTINE, VINCRISTINE, VINORELBINE t adverse effects of vinblastine and vincristine Inhibition of CYP3A4-mediated metabolism. Also inhibition of P-gp efflux of vinblastine Monitor FBCs. Watch for early features of toxicity (pain, numbness, tingling in the fingers and toes, jaw pain, abdominal pain, constipation, ileus). Consider selecting an alternative drug... 

Erythromycin increased the toxicity of vinbiastine in three patients. Clarithromycin possibly does not interact with vinca alkaloids. 

Information seems to be limited to this report. On the basis of their findings the authors suggest that erythromycin should be avoided at the time of vinblastine infusion. Use with clarithromycin may be safe. The UK manufacturers of vincristine and vindesine have warned that caution should be exercised in patients taking any drugs known to inhibit the CYP3A subfamily because of the risk of an earlier onset and/or increased severity of adverse effects. One manufacturer of vinblastine states that erythromycin may increase vinblastine toxicity. Note that itraconazole, another CYP3A4 inhibitor, is known to increase the toxicity of vincristine, see Vinca alkaloids -i- Azoles , p.668. 

---