- Prior treatment with sulfonylurea, or metformin within 21 days before study entry, prior treatment with NSAIDs, or diuretics within 21 days of screening, serum creatinine levels above 1.5 mg/dl for males or above 1.4 for females or creatinine clearance less than 70 ml/min by Cockcroft and Gault, or serum albumin levels of less than 2.5 gm/dl.