Abstract
This paper reports a case of Grade IV thrombocytopenia in a 65-year-old male patient with advanced lung cancer after 4 days of concurrent treatment with selpercatinib and voriconazole. The clinical pharmacist attributed the thrombocytopenia to voriconazole exacerbating the hematological toxicity of selpercatinib and thus stopped selpercatinib and voriconazole treatment sequentially; the patient was given recombinant human thrombopoietin to raise platelets. When the platelet count returned to normal and voriconazole was discontinued, selpercatinib was restarted at a reduced dose and gradually titrated back to the original therapeutic dose. Subsequent treatment did not have any further adverse reactions. This case suggests that doctors and clinician pharmacists should be aware of the potential interaction between selpercatinib and voriconazole, avoid the use of CYP3A4 inhibitors during selpercatinib treatment, and pay attention to dose adjustment.