Abstract
A 66 year-old woman was referred to our clinic with a complaint of severe tongue pain resulting from dental treatment 9 years earlier. First she received stellate ganglion block, oral am itriptylin and etizolam. After observation of the effectiveness of lidocaine and ketamine hydrochloride by drug challenge test, she also started oral mexiletine, and finally intravenous ketamine infusion therapy successfully reduced her pain. However, she had skin eruption 69 days after her first visit. Although we discontinued every medication, skin eruption deteriorated and she experienced transient liver dysfunction and significant increase of HHV-6 IgG Ab. Her clinical features, clinical course and the positive result on a patch test for mexiletine indicated that she had hypersensitivity syndrome. Mexiletine is effective in the treatment of pain, but we should be aware of its potential adverse side effects.
