All of the following are inotropic drugs except:
a. AMIODARONE is a class III antiarrhythmic drug and not an inotropic drug. It acts by prolongation of APD and ERP at the AV node, conducting tissue, ventricular fibers and atria.
b. Photosensitization, skin pigmentation and hypothyroidism are important side effects. Amrinone is a selective phosphodiesterase III inhibitor. Amiodarone blocks all the receptors e.g. Na+, calcium, beta, and potassium.
c. To be able to act as a drug that will have inotropic action; the drug should increase cAMP inside myocardium. This could be done by stimulating beta adrenergic receptors or by inhibiting its breakdown.