The Effect of Ruboxistaurin on Small Fiber Function

Inclusion Criteria: * Patients must have Type 1 or Type 2 diabetes mellitus * Patients must have bilateral sensorimotor distal peripheral neuropathy attributable to diabetes mellitus * Patients must have blood glucose control measured as HbA1c=\<11% * Patients must be 18 years of age or older. * Patients must be able to return to all follow-up visits Exclusion Criteria: * Patients must not have symptoms of diabetic peripheral neuropathy that cannot be distinguished from other etiologies * Patients must not have a neurologic disease or neuropathy from a cause other than diabetes mellitus that would interfere with correct evaluation of symptomatic peripheral neuropathy. * Patient currently has uncontrolled high blood pressure * You have other medical problems that your doctor feels would make it unsafe for you to participate in this study such as liver or kidney problems * You are a woman of childbearing age and unwilling or unable to use effective contraceptive.