Microalbuminuria and Allopurinol in Type 1 Diabetes

Inclusion Criteria: * Albuminuria (≥30 mg/g) * Uric Acid ≥ 0,265 mmol/l * GFR (glomerular filtration rate) \> 40 ml/min/1.73m2 Exclusion Criteria: * History of gout or xanthinuria or other indications for uric acid lowering therapy such as cancer chemotherapy. * Recurrent renal calculi. * Current use of azathioprine, 6-mercaptopurine, didanosine, tamoxifen, amoxicillin/ampicillin, or other drugs interacting with allopurinol. * Known allergy to xanthine-oxidase inhibitors. * Renal transplant. * Non-diabetic kidney disease. * Home, 24h og clinical BP\>180 or Diastolic BP \>130 mmHg at screening. * Cancer treatment within two years before screening. * History of hepatitis B or C. * History of acquired immune deficiency syndrome or human immunodeficiency virus (HIV) infection. * History of alcohol or drug abuse. * Breastfeeding or pregnancy or unwillingness to be on contraception throughout the trial. * Poor mental function or any other reason to expect patient difficulty in complying with the requirements of the study. * Serious pre-existing medical problems other than diabetes, e.g. congestive heart failure, pulmonary insufficiency.