Effectiveness, tolerability, and impact on quality of life of the 5% lidocaine patch in diabetic polyneuropathy.

BACKGROUND The treatment of painful diabetic polyneuropathy (DPN) is often inadequate and frequently limited by the systemic adverse effects of medications, necessitating the evaluation of novel treatments. OBJECTIVE To evaluate the effectiveness, tolerability, and impact on quality of life of the 5% lidocaine patch in painful diabetic polyneuropathy. DESIGN Open-label, flexible-dosing, 3-week study with a 5-week extension. SETTING Outpatient clinics and clinical research centers.Patients Volunteer sample of 56 patients with clinically defined painful diabetic polyneuropathy of longer than 3 months' duration. Intervention The 5% lidocaine patch, with a maximum of 4 patches daily for 18 hours. MAIN OUTCOME MEASURES Change in mean daily pain diary ratings from baseline to week 3. Secondary end points included assessments of safety, tolerability, and quality of life. RESULTS Patients with painful diabetic polyneuropathy showed significant improvements in pain and quality-of-life outcome measures during a 3-week treatment period. These benefits were maintained in a subgroup of patients treated for an additional 5 weeks, during which taper of concomitant analgesic therapy was permitted. Adverse events were minimal, and systemic accumulation of lidocaine did not occur. CONCLUSIONS Up to four 5% lidocaine patches for up to 18 h/d are well tolerated in patients with painful diabetic polyneuropathy, significantly improve pain and quality-of-life ratings, and may allow tapering of concomitant analgesic therapy. Given the open-label design of this trial, a randomized controlled trial is necessary to confirm these results.