Mexiletine for the Treatment of Refractory Chronic Migraine: A Retrospective Chart Review
Lucia Liao1, Dylan Selbst1, Emily Casaletto1, Hsiangkuo Yuan2, Clinton Lauritsen3
1Neurology, Thomas Jefferson University, 2Jefferson Headache Center, 3Thomas Jefferson University Hospital
Objective:
This is the first study to describe dosing, time to discontinuation, and adverse effects of mexiletine in a complete cohort of patients for migraine treatment.
Background:
Intravenous lidocaine infusion is commonly used at Thomas Jefferson Headache Center during inpatient admission for treatment of refractory chronic migraine. Patients are subsequently discharged on mexiletine (similar to lidocaine, a class 1B sodium channel antagonist) as a new daily preventive medication.
Design/Methods:
Electronic medical records were reviewed of 373 patients admitted for first-time lidocaine infusion for refractory chronic migraine between 1/2019- 4/2020 with ≥ 1 post-discharge follow up visit. Pain scores were collected at time of admission, discharge, and at up to 6 office visits within 1 year post discharge.
Results:
After lidocaine infusion, almost all patients were initially prescribed a daily dose of mexiletine 450 mg (150 mg TID). Patients who discontinued mexiletine due to side effects usually did so at this starting dose. The median final total daily dose for patients who remained on mexiletine was 600 mg (ranging 150 mg to 1350 mg).
40% of patients were still taking mexiletine around 500 days after discharge and 30% of patients were still taking mexiletine around 700 days on Kaplan-Meier curves. The two most common reasons for discontinuation were side effects (57%) and inadequate treatment response (17%). Nausea, vomiting, dizziness, and tremor were the most common side effects.
Wilcox test of pain scores and monthly headache days at the first office visit compared to admission was highly statistically significant (p-value<0.00001). However, there was no correlation between pain scores and mexiletine doses/levels.
Conclusions:
Dizziness during lidocaine administration (p-value=0.0008) and lower tolerated lidocaine infusion rates (p-value=0.001) were predictive of shorter number of days on mexiletine treatment. A lower starting dose should be considered on these patients. Further research is needed on the direct effectiveness of mexiletine in migraine treatment.