Drug Eruption due to Mexiletine and Diltiazem

Abstract

A 68-year-old man with ischemic heart disease, who had taken mexiletine and diltiazem for 3 weeks, developed exfoliative dermatitis with a fever. A few days after the initial administration, a laboratory examination showed a slight increase in the GOT and GPT levels. Thereafter, oral prednisolone was administered and the condition improved. However, even though the drug was discontinued the exanthema recurred six weeks later. The patient was successfully treated by systemic corticosteroid therapy. Patch tests using 1%, 10%, 30% mexiletine and diltiazem in petrolatum showed positive results. A lymphocyte stimulation test was negative. In addition to this case, 37 cases of drug eruption due to mexiletine and 39 cases of drug eruption due to diltiazem have been reported in Japan. Several common clinical features were observed in these drug eruptions. First, the interval between the start of the drug and onset of the eruption was relatively long (48∼88days). Second, the positive percentage of the patch test was high (86∼97%), whereas positive percentage of the lymphocyte stimulation test was low (23∼27%). Third, the patients frequently showed systemic symptoms, e.g., fever (93∼94%) and liver dysfunction (43∼78%). Fourth, some patients including this case had multiple drug eruptions.