Their metabolism is mediated by the CYP3A4 pathway; therefore, inhibition of the CYP3A4 pathway can increase blood concentrations of epipodophyllotoxins with an increased risk of mucositis, liver toxicity and myelosuppression (Antoniou and Tseng, 2005; Beumer et al., 2014). Here, CYP3A4 is linked to mucositis.