Abstract
A 49-year-old woman, who had been diagnosed with multiple sclerosis (MS) 24 years ago, was suffering from right facial pain for 11 years. During this time, her pain had been treated with various methods, including medication, nerve block, and gamma knife. The pain worsened, and her blood carbamazepine reached toxic levels a few weeks before admission. Therefore she was admitted to our hospital for pain management and to reduce her total carbamazepine levels. Cranial MRI and the blink-reflex test were consistent with symptomatic trigeminal neuralgia (TN) secondary to MS lesions in the pons and medulla.The levels of carbamazepine were reduced. Nine days after admission, she was prescribed codeine phosphate (40 mg/day) that showed a higher efficacy for her trigeminal neuralgia. Opioids should be considered in the case of intractable TN when antidepressant and antiepileptic drugs have been insufficiently working.