MEXILETINE IN THE TREATMENT OF PAINFUL DI ABETIC NEUROPATHY

The objective of this double-blind placebo controlled multicenter stud y was to prove the efficacy of mexiletine in painful diabetic neuropat hy. Treatment was provided for in three dosages. For pain measurements a visual analogue scale (VAS) and McGill's verbal rating scale were c hosen. 95 patients were included. A global assessment of the VAS showe d no differences in treatment. The total evaluation (PRIT = Pain Ratin g Index Total) of the McGill scale just failed the level of significan ce. More specific exploratory evaluation of subclasses of the McGill s cale, representing different qualitites of pain, gave remarkable diffe rences between mexiletine and placebo. According to types of complaint s an evaluation showed substantial advantages of the mexiletine treatm ent with both the VAS and the McGill scale. There is strong evidence t hat particularly patients with stabbing or burning pain, heat sensatio ns or formication will benefit most by mexiletine therapy. Concerning the dosage, a medium regimen of 450 mg per day seems to be appropriate in this indication. With an increase in dosage the efficacy does not rise proportionally. Mexiletine proved a very safe therapy with neglig ible side effects at the medium dose range, even less than placebo. Th ere were no cardiovascular side effects. Further investigations should pay more attention to the variety of the complaints and include the q uality of life.