Combination use of beta blockers and calcium channel blockers cause -

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.