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
A patient on warfarin was given phenobarbitone, The result would have been - 
Select and explain. 
A. Increase the dose of warfarin, B. Decrease the dose of warfarin, C. Increase the dose of phenobarbitone, D. Decerease the dose of phenobarbitone
A: Increase the dose of warfarin
Answer: A: Increase the dose of warfarin 
Explanation: Ans. is 'a' i.e., Increase the dose of warfarin