Dopamine is preferred over dobutamne in treatment of renal shock because: March 2011
## **Core Concept**
Dopamine and dobutamine are both catecholamines used in the treatment of shock, including renal (or cardiogenic) shock. They have different receptor affinities and effects on the cardiovascular system. The core concept here involves understanding the pharmacodynamics of these drugs, particularly their effects on renal blood flow and vascular resistance.
## **Why the Correct Answer is Right**
Dopamine is preferred over dobutamine in the treatment of renal shock because at low doses (1-2 μg/kg/min), dopamine predominantly stimulates **dopamine receptors** in the renal and mesenteric blood vessels, causing vasodilation. This effect can potentially improve renal perfusion and function. Additionally, dopamine has a positive effect on cardiac output at higher doses. Dobutamine, on the other hand, primarily stimulates **beta-1 adrenergic receptors**, increasing heart rate and contractility but not providing the same level of renal vasodilation as low-dose dopamine.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is blank and thus cannot be evaluated.
- **Option B:** This option is also blank and cannot be assessed.
- **Option C:** Similarly, this option does not provide any information to evaluate its correctness.
- **Option D:** This option is the correct answer but without the text, we can't directly assess why it's wrong based on the provided information.
## **Clinical Pearl / High-Yield Fact**
A key clinical point to remember is that the use of low-dose dopamine to improve renal function is debated, and its benefits may be more theoretical than proven in clinical practice. However, in certain scenarios, particularly where there's a concern about maintaining renal perfusion, dopamine might still be considered. It's also crucial to note that the evidence supporting the routine use of dopamine for renal protection in shock is limited.
## **Correct Answer:** D.