Multicentre, double-blind, crossover trial to identify the Optimal Pathway for TreatIng neurOpathic paiN in Diabetes Mellitus (OPTION-DM): study protocol for a randomised controlle... oleh Dinesh Selvarajah, Jennifer Petrie, David White, Steven Julious, Oscar Bortolami, Cindy Cooper, Mike Bradburn, Amanda Loban, Helen Bowler, Lizzie Swaby, Katie Sutherland, Solomon Tesfaye, on behalf of the OPTION-DM group