Benfotiamine in Diabetic Nephropathy

Inclusion Criteria: * Type 2 diabetes mellitus * Patients are on treatment with angiotensin converting enzyme inhibitors (ACEi) and/or angiotensin II antagonists (AIIA) in an unchanged dose for at least 3 months * Active diabetic nephropathy as indicated by presence of microalbuminuria (15-300 mg/24 h urine) in at least two samples within 2-6 weeks in advance of inclusion in the trial * HbA1c \< 8.5%, a higher HbA1c \< 9.5% is acceptable if the treating physician and the patient have accepted that striving for lower values is an unreachable goal (patients with high HbA1c values are the ones that one would expect to be benefit most from treatment with benfotiamine) * eGFR (estimated by MDRD formula) \> 30 ml/min * Males and postmenopausal females * Written informed consent Exclusion Criteria: * Renal impairment by other causes than diabetes * Stage of the disease more severe than indicated in Inclusion criteria (macroalbuminuria or renal insufficiency) * Severe hypoglycemia during the last 3 months, needing help from another person * Severe hepatopathy (laboratory values about three times higher than normal * Endocrine disorders, e.g. hyper/hypothyroidism * Blood pressure \> 160/90 mmHg * Severe cardiac function disturbances and severe heart rhythm disturbances * Neoplasm's (excluding history of treated skin cancer of the type basal cell carcinoma BCC or squamous cell carcinoma SCC) * Severe general diseases or mental disorders making the participation in the study impossible * Drug abuse * Female patients during pregnancy and lactation period and female patients with active menses during the past year * Hypersensitivity to benfotiamine * HbA1c \> 9.5% * Use of thiamine containing supplements during the last 3 months * Participation in another study within one month before joining the benfotiamine study