Rai-refractory, advanced differentiated thyroid cancer receiving kinase inhibitor treatment: Checking for drug-drug interactions

With the introduction of multitargeted kinase inhibitors (KIs) for the treatment of individuals with radioiodine-refractory differentiated thyroid carcinoma, new patient safety risks have appeared that require extreme caution on the part of all physicians involved in these patients (Carhill et al., J Clin Endocrinol Metab 98:31-42, 2013; Cabanillas et al., Endocr Rev 40:1573-604, 2019). These adverse events range from common toxicities, such as diarrhea and skin rashes, to uncommon events that can occasionally be life-threatening, such as prolongation of QT intervals that can trigger arrhythmias. Those adverse events that are directly related to the concentration of the drug in circulation can be potentiated by concomitant use of other drugs that alter the metabolic clearance or pharmacokinetics of the KI itself. Thus, knowledge of the potential for drug-drug interactions is critical whenever medications are prescribed for a thyroid cancer patient being treated for metastatic disease with a KI. Patient education is also critical, so that the patient is able to alert whomever is prescribing a medication for them to check for possible drug-drug interactions that either increase risk or decrease the effectiveness of the KI.