<prompt> In treatment of shock Dobutamine is preferred over Dopamine because?It causes less arrhythmiaIt causes less renal vasodilatationIt causes less coronary vasoconstrictionAll the above  <response>: ANSWER: D All of the aboveREF: KDT 5th edp.470DopamineActs on D1 , D2 , alpha and betal receptorsLow doses: renal vasodilation D1 actionModerate doses: Positive ionotropism betal action High doses: Vasoconstriction alphal actionDobutamineRelatively betalspecific agonistIonotropic i.e increases force of cardiac contraction without causing vasoconstriction . increasing afterload, heart rate or BP.Therefore since dobutamine is betal specific, doesnt cause vasoconstriction, it is less arrythmogenic, and doesnt affect renal vasculature it is preferred in cardiogenic shock, however it is less suitable for shocks in which vasoconstriction is required. 