Questions

A patient is taking 1000 mg sulfamethoxazole tablet every 12 hours for the treatment of urinary tract infection. Sulfamethoxazole is rapidly and completely absorbed after oral administration and its renal clearance represent 20% of its total body clearance. What is the amount of sulfamethoxazole eliminated unchanged in urine during one dosing interval at steady state ?

1 - 500 mg / 12 hours 2 - 200 mg / 12 hours 3 - 1000 mg / 12 hours 4 - 400 mg / 12 hours