This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Pharmacology
Which of the following statments about the biodisposition of penicillins and cephalosporins is NOT accurate? 
Select and explain. 
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 minly biliary secretion
C: Renal tubular reabsorption of beta-lactams is inhibited by probenecid
Answer: C: Renal tubular reabsorption of beta-lactams is inhibited by probenecid 
Explanation: (Ref: KDT 6/e 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).