An open-label study of the lidocaine patch 5% in painful idiopathic sensory polyneuropathy.

OBJECTIVE: Painful idiopathic distal sensory polyneuropathy is common, but has been largely ignored as a model for the evaluation of neuropathic pain therapies. We have therefore conducted a safety, tolerability, and effectiveness study of the lidocaine patch 5% in painful idiopathic distal sensory polyneuropathy.
DESIGN: A prospective open-label, flexible dosing, 3-week study period with a 5-week extension.
SETTING: Peripheral Neuropathy clinics and Anesthesiology Clinical Research Center at a tertiary care facility. PATIENTS: Twenty subjects with a diagnosis of idiopathic distal sensory polyneuropathy (with or without associated impaired glucose tolerance), with a baseline mean pain daily rating of > or =4 on a visual analog scale. Intervention. Lidocaine patch 5%, maximum of four patches daily for 18 hours. MAIN OUTCOME MEASURE: Change from baseline week to week 3 mean daily diary pain ratings. Secondary endpoints included assessments of safety and tolerability as well as quality of life measures.
RESULTS: Subjects with idiopathic distal sensory polyneuropathy, both with and without impaired glucose tolerance, showed significant improvements in pain and quality of life outcome measures over a 3-week treatment period. These improvements were maintained in a subgroup of patients treated for an additional 5 weeks and permitted a taper of concomitant analgesics in 25% of subjects. The lidocaine patch 5% was well tolerated.
CONCLUSIONS: The lidocaine patch 5% appeared well tolerated and potentially effective in the management of painful idiopathic distal sensory polyneuropathy. Idiopathic distal sensory polyneuropathy is an appropriate patient population for the conduct of clinical trials of neuropathic pain therapies.