This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Acid Labile penicillin is- 
Select and explain. 
A. Cloxacillin, B. Flucloxacillin, C. Methicillin, D. Phenoxy Methyl penicillin
C: Methicillin
Answer: C: Methicillin 
Explanation: Ans. is 'c' i.e., Methicillin o Gastric acid destroyes the penicillins and decreases their bioavailibility. o All penicillins are acid labile accept phenoxymethyl penicillin (penicillin V), Cloxacillin, Flucloxacillin, Oxacillin, Dicloxacillin, ampicillin. Note - Cloxacillin, flucloxacillin, oxacillin, and dicloxacillin are resistant to both acid as well as penicillinase.