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
Combination use of beta blockers and calcium channel blockers cause - 
Select and explain. 
A. Hea block, B. Hypeension, C. Hypotension, D. All
A: Hea block
Answer: A: Hea block 
Explanation: Ans. is 'a' i.e., Hea block o CCBs (verapamil, diltiazem) have negative chronotropic effect (| SA node automaticity -| hea rate) and negative dromotropic effect (1AV node conduction). o b-blockers have similar effect by blocking b1 sympathetic receptors on hea (normally stimulation of b1 receptors increases hea rate and conduction). o Simultaneous use of these drugs can cause marked bradycardia and AV block. Amongst CCBs, DHPs (nefidipine) can be used with b-blockers because DHPs have no direct negative chronotropic and dromotropic effect, rather they cause tachycardia by reflex sympathetic stimulation.