During dopamine therapy, the low-dose range (dopaminergic activity) is which of the following?

During dopamine therapy, the low-dose range (dopaminergic activity) is which of the following?

• A. 0.5-2 mcg/kg/min
• B. 1-3 mcg/kg/min
• C. 3-10 mcg/kg/min
• D. >10 mcg/kg/min

Answer: (B)

Dopamine’s effects change with the dose because different receptors predominate at different infusion rates. At low doses, dopaminergic (D1) receptors dominate, causing dilation of renal and mesenteric vessels and increased renal perfusion. This dopaminergic window is typically described as around 1–3 mcg/kg/min, which is why this range is the correct answer. At higher doses, beta-1 effects become more prominent (increasing heart rate and contractility) and, at still higher doses, alpha-adrenergic effects cause vasoconstriction. So, 1–3 mcg/kg/min best represents the dopaminergic, low-dose range.

Dopamine’s effects change with the dose because different receptors predominate at different infusion rates. At low doses, dopaminergic (D1) receptors dominate, causing dilation of renal and mesenteric vessels and increased renal perfusion. This dopaminergic window is typically described as around 1–3 mcg/kg/min, which is why this range is the correct answer. At higher doses, beta-1 effects become more prominent (increasing heart rate and contractility) and, at still higher doses, alpha-adrenergic effects cause vasoconstriction. So, 1–3 mcg/kg/min best represents the dopaminergic, low-dose range.