This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Dobutamine causes - 
Select and explain. 
A. Increased cardiac output, B. Marked increase in hea rate, C. Increased total peripheral resistance, D. Marked increase in BP
A: Increased cardiac output
Answer: A: Increased cardiac output 
Explanation: Ans. is 'a' i.e., Increased cardiac output o Only prominent action of dobutamine is in increase in force of cardiac contraction and cardiac output without significant change in hea rate, peripheral resistance and BP. o In comparison to dopamine, dobutamine :? i) Does not cause renal or mesentric vasodilation. ii) Does not cause coronary vasoconstriction (no effect on alpha receptors). iii) Does not cause release of endogenous norepinephrine and does not precipitate arrythmia. If has an effect on peripheral resistance , always decreases it (Dopamine can increase or decrease peripheral resistance depending on the dose).