DURICEF is rapidly absorbed after oral administration. Following single doses of 500 mg and 1000 mg, average peak serum concentrations were approximately 16 and 28 μg/mL, respectively. Measurable levels were present 12 hours after administration. Over 90% of the drug is excreted unchanged in the urine within 24 hours. Peak urine concentrations are approximately 1800 μg/mL during the period following a single 500 mg oral dose. Increases in dosage generally produce a proportionate increase in DURICEF (cefadroxil monohydrate, USP) urinary concentration. The urine antibiotic concentration, following a 1 g dose, was maintained well above the MIC of susceptible urinary pathogens for 20 to 22 hours.^[1]

Adapted from the FDA Package Insert.