Pharmacokinetics of norfloxacin (MK 366) in patients with impaired kidney function--some preliminary results.

The concentration of norfloxacin in serum and urine was measured in five healthy volunteers and eleven patients with renal impairment following a 400 mg oral dose of norfloxacin. In impaired renal function the elimination rate of norfloxacin is decreased considerably whereupon the area under the curve (AUC) rises rapidly. The urinary concentration of norfloxacin decreases with renal function but therapeutic levels are still obtained for sensitive organisms. Patients with a glomerular filtration rate of less than 30 ml/min require dosage reduction and we would recommend a reduction to half the usual dosage.