<prompt> Which of the following statments about the biodisposition of penicillins and cephalosporins is NOT accurate?Oral bioavailability is affected by lability to gastric acidProcaine penicillin G is used intramuscular injectionRenal tubular reabsorption of beta-lactams is inhibited by probenecidNafcillin and ceftriaxone are eliminated minly biliary secretion  <response>: Ref: KDT 6e p697 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. 