All of the following drugs undergo hepatic metabolism before excretion, EXCEPT:
The pharmacokinetics of Penicillin G is dominated by very rapid renal excretion. About 10% of the drug is eliminated by glomerular filtration and rest by tubular secretion. The plasma t1/2 of penicillin G in healthy adults is 30 minutes. Ref: Essentials of Medical Pharmacology By K D Tripathi, 5th Edition, Pages 364, 372, 589, 655
Phenytoin
Diazepam
Penicillin G
Cimetidine