Background: Background: Intravenous lidocaine has multiple applications in the management
of acute and chronic pain. Mexiletine, an oral lidocaine analogue, has been used in a number of
chronic pain conditions although its use is not well characterized.
Objectives: To report our experience using mexiletine in a chronic pain population, specifically
looking at tolerability, side effects, and EKG changes.
Study Design: Retrospective, cohort study.
Setting: Multiple pain clinic locations in an integrated multispecialty health system.
Methods: All patients who had a mexiletine prescription between August 2015 and August 2016
were queried via the electronic medical record. Each chart was examined for demographics, QTc
changes on EKG, length of use, and reasons for stoppage.
Results:There were 74 total patients identified in the chronic pain management clinics as
receiving at least 1 mexiletine prescription over the 1-year time period. Twice as many women as
men received mexiletine prescriptions. Neuropathic pain was the most common primary diagnosis
(64%) which included diabetic neuropathy, radiculopathy, and others. Fibromyalgia was the next
most common primary diagnosis (28%). A QTc change on the EKG showed a mean decrease
of 0.1 ms and median increase of 1.5 ms. At 6 months (180 days), approximately 30% of the
patients remained on mexiletine therapy, and 28% remained on the therapy at 1 year (360 days).
Median duration of use was 60 days and the mean was 288 days. Neurologic and gastrointestinal
side effects were the most commons reason for stoppage. All side effects were mild and resolved
with stoppage. After side effects, lack of response, or loss of efficacy, were the next most common
reasons for stoppage.
Limitations: Pain relief and outcomes were not specifically examined due to confounding factors
including interventional treatments and multiple treatment modalities. This was a retrospective,
cohort study limited to our specific clinic population with a relatively high loss to follow-up rate.
Conclusion:Mexiletine is rarely a first line option for chronic pain management and is often
used when multiple other modalities have failed. By reporting our experience, we hope other
clinicians may have more familiarity with the drug’s use in a chronic pain practice. It appears
reasonably tolerable, may not require frequent EKG monitoring, and can be an appropriate adjunct
in the chronic pain population. More research is needed regarding efficacy and dose titration for
mexiletine in chronic pain.
Key Words: Chronic pain, mexiletine, IV lidocaine, pain, neuropathic pain, neuropathy,
fibromyalgia, QTc, tolerability
