Dopamine can elevate blood pressure, and it may do so in moderate or high doses. Because of the positive inotropic effect on the myocardium in medium doses, the contractility and blood ejection of the myocardium are increased and the systolic blood pressure can be raised, and in large doses the vascular resistance can be increased and the renal vasoconstriction can be caused, which finally leads to the elevation of both systolic and diastolic blood pressures. If dopamine is used in small doses, it can increase the blood flow to the kidney and can improve the perfusion of the kidney, which will cause a decrease in blood pressure instead. Therefore, dopamine is used in various kinds of shock, congestive heart failure, cardiac arrest and so on.