Keywords: dopamine, dobutamine, cardiogenic shock (PubMed Search)
Traditional teaching for patients with hypotension in the setting of MI and heart failure (i.e. not just RV MI) is to give dobutamine as a first-line agent when the SBP is 80-100, and to use dopamine when the SBP is 70-80s [note that this recommendation is NOT based on good evidence, but primarily on consensus opinion]. The problem with using these medications, especially at higher doses (e.g >10-15 mcg/kg/min) is that they result in excessive alpha-1 adrenergic stimulation that can produce end-organ ischemia.
However, there is some evidence that rather than using high dosages of dobutamine or dopamine, "the deliberate combination of dopamine and dobutamine at a dose of 7.5 mcg/kg/min each was shown to improve hemodynamics and limit important side effects compared with [high dosages of] either agent [alone]."
[Overgaard CB, Dzavik V. Inotropes and vasopressors: review of physiology and clinical use in cardiovascular disease. Circulation 2008;118:1047-1056.]