This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CHF, Angina Pectoris and Myocardial Infarction, Subject name: Pharmacology
Which of the following is a K+ channel opener? 
Select and explain. 
A. Ranolazine, B. Nicorandil, C. Verapamil, D. Lignocaine
B: Nicorandil
Answer: B: Nicorandil 
Explanation: NICORANDIL:- K+ channel opener NO releaser Given for Angina Drug activates ATP sensitive K+ channels --> Hyperpolarizing vascular smooth muscle. Nicorandil is believed to exe cardioprotective action by simulating 'ischaemic preconditioning' as a result of activation of mitochondrial K-ATP channels. Ranolazine - Inhibits late phase of sodium current (Late I Na) improving oxygen supply and demand equation. It has antianginal as well as antiarrhythmic propeies. Verapamil :- calcium channel blocker, slows AV conduction directly and decrease HR, contractility, BP and oxygen demand. Lidocaine : class IB antiarrhythmic drug, shoens phase 3 repolarization and decrease the duration of action