<prompt> Which of the following best describes a pharmacologic propey of amiodarone?a-Adrenergic agonistb-Adrenergic agonistActivation of Ca 2 channelsInhibition of K channels  <response>: Amiodarone Mech of action:- It is iodine containing highly lipophilic long-acting antiarrhythmic drug exes multiple actions: Prolongs APD and Q-T interval attributable to block of myocardial delayed rectifier K channels. This also appears to reduce non-uniformity of refractoriness among different fibres. Preferentially blocks inactivated Na channels like lidocaine with relatively rapid rate of channel recovery: more effective in depressing conduction in cells that are paially depolarized or have longer APD. Paially inhibits myocardial Ca2 channels, has noncompetitive b adrenergic blocking propey and alters thyroid function. Ref:- kd tripathi; pg num:-533 