Which of the following statements about the biodisposition of penicillins and cephalosporins is NOT accurate?: (A) Oral bioavailability is affected by lability to gastric acid, (B) Procaine penicillin G is used intramuscular injection, (C) Renal tubular reabsorption of beta-lactams is inhibited by probenecid, (D) Nafcillin and ceftriaxone are eliminated mainly biliary secretion
Answer is C. * Probenecid inhibits renal tubular secretion of penicillins (not reabsorption) * Beta lactams eliminated by biliary route are: -- Ampicillin -- Nafcillin -- Ceftriaxone -- Cefoperazone * Penicillin G has to be given by i.m. route because it is broken down by gastric acid (decreases oral bioavailability).