A drug effect that is produced by therapeutic doses of both timolol and amiodarone is blockade of:: (A) Cardiac Na+ channels, (B) Cardiac K+ channels, (C) Beta adrenoceptors, (D) Alpha-adrenoceptors
Answer is C. Amiodarone has wide spectrum of antiarrhythmic actions. It acts by all the four mechanisms: blockade of Na+ channels blockade of b receptors blockade of K+ channels blockade of Ca2+channels. Timolol is a b blocker. Therefore, common action of these two drugs is inhibition of b-receptors.