Why it works?
We use DOBUTamine for heart failure because DOBUTamine only increases the heart muscle contractility (inotropic) but not the peripheral blood vessels (too little alpha 1 effects to have any effects).
In heart failure, the heart itself has already failed to contract due to myopathy. Using DOBUTamine would increase the heart's inotropic effects without vasoconstriction causing increased peripheral blood vessel increase.
If you use DOPamine, you can cause inotropic (b1 agonist) and increased peripheral pressure due to vasoconstriction (a1 agonist). The a1 agonist effect will cause increased blood pressure forcing the heart to work even harder. This is not good for an already weak heart (heart failure). Therefore, DOBUTamine is preferable.
Now, if you have a shock case in which the heart beats too slowly and the blood pressure is too low but the total blood volume is not lost, you can use DOPamine to increase heart rate (beta1 effects) and vasoconstriction (alpha 1 effects). And, theoretically, DOPamine is preferred over other vasopressors for shock because it perfuses the renal functions thru the dopaminergic receptors (DA receptor).
(thanks to my bf for explaining this to me :))
~Wonder Me!
We use DOBUTamine for heart failure because DOBUTamine only increases the heart muscle contractility (inotropic) but not the peripheral blood vessels (too little alpha 1 effects to have any effects).
In heart failure, the heart itself has already failed to contract due to myopathy. Using DOBUTamine would increase the heart's inotropic effects without vasoconstriction causing increased peripheral blood vessel increase.
If you use DOPamine, you can cause inotropic (b1 agonist) and increased peripheral pressure due to vasoconstriction (a1 agonist). The a1 agonist effect will cause increased blood pressure forcing the heart to work even harder. This is not good for an already weak heart (heart failure). Therefore, DOBUTamine is preferable.
Now, if you have a shock case in which the heart beats too slowly and the blood pressure is too low but the total blood volume is not lost, you can use DOPamine to increase heart rate (beta1 effects) and vasoconstriction (alpha 1 effects). And, theoretically, DOPamine is preferred over other vasopressors for shock because it perfuses the renal functions thru the dopaminergic receptors (DA receptor).
(thanks to my bf for explaining this to me :))
~Wonder Me!
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