Nafcillin biliary excretion

Nafcillin is primarily cleared by biliary excretion. Oxacillin, dicloxacillin, and cloxacillin are eliminated by both the kidney and biliary excretion no dosage adjustment is required for these drugs in renal failure. Because clearance of penicillins is less efficient in the newborn, doses adjusted for weight alone result in higher systemic concentrations for longer periods than in the adult. 

Nafcillin is primarily cleared by biliary excretion while dicloxacillin is eliminated by both kidney and biliary excretion. No dose adjustments are needed in the setting of renal or hepatic dysfunction. 

Antimicrobial drugs that are eliminated via hepatic metabolism or biliary excretion include erythromycin, cefoperazone, clindamycin, doxycycline, isoniazid, ketoconazole, and nafcillin. The answer is (C). 

Excretion The primary route of excretion is through the organic acid (tubular) secretory system of the kidney (see p. 224), as well as by glomerular filtration. Patients with impaired renal function must have dosage regimens adjusted. Thus the Xyz of penicillin G can increase from a normal of 1/2 -1 hour to 10 hours in individuals with renal failure. Probenecid inhibits the secretion of penicillins. Nafcillin is primarily eliminated through the biliary route. [Note This is also the preferential route for the acylureido penicillins in cases of renal failure.]... 

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