To know the blood level of allopurinol in chronic kidney disease (CKD) patient.

After the result of this pilot study, we can prescribe the optimal dose of allopurinol in CKD patient.

Inclusion Criteria:

• from 18yrs to 80yrs , man and women
• the patient who are taking allopurinol
• On screening, the patient shows that the level of protein/creatinine ratio is over 3.0
• On screening, the patient shows that MDRD GFR >= 30 ml/min and <= 60 ml/min
• the patient sign on the concent form

Exclusion Criteria:

• the patient have experience to take medication that have an effect on renal function
• the patient have experience to take cyclosporin within 3month
• At least, the average level of two separate blood pressure ( 2min interval ) shows that SBP <= 100 mmHg or >=160 mmHg and DBP <=60 mmHg >=100 mmHg, or Heart rate < 40 beats/min or > 90 beats/min
• uncontrolled hypertension
• pregnancy or anticipate pregnancy with 6 month
• hypersensitivity to allopurinol
• acute hepatitis or the level of AST or ALT is over 2times of normal range or the level of bilirubin is over 2.0 mg/dL
• serum albumin < 3.5 mg/dL or > 5mg/dL
• urinary retension, prostatic hyperplasia
• the patient show gout attack on taking allopurinol
• the patient who have gastro-intestinal disease ( ex, crohn's disease, acute or chronic pancreatitis, ulcer )or who have the surgical history of gastrointestine.
• the patient who should take azathioprine, mercaptopurine, cyclophosphamide, Losartan, benzbromarone,fenofibrate,furosemide ,probenecid
• the patient who had taken part in the other study within 3months
• the patient who had gotten blood transfusion
• pregnant, breast feeding

chronic kidney disease ( estimated GFR 30-60 ml/min )