Which statement best describes the pharmacodynamic basis for using low-dose dopamine as a 'renal-dose' agent, and why this practice is now questioned?

• A Beta-1 receptor stimulation increases cardiac output, increasing renal perfusion; questioned because it causes excessive tachycardia
• B Alpha-1 agonism at renal arteries reduces vascular resistance; abandoned due to systemic hypertension
• C D2 receptor inhibition prevents tubular sodium reabsorption; ineffective in volume-depleted states
• D DA1-mediated renal vasodilation increases GFR; but controlled trials show no reduction in AKI incidence or need for dialysis ✓

Explanation

Dopamine at 1–3 mcg/kg/min activates DA1 (D1-like) receptors in the renal vasculature and tubules, causing vasodilation of the afferent arterioles and modest natriuresis. This was theorized to protect against AKI. However, multiple randomized controlled trials (including the ANZICS trial) found that low-dose dopamine conferred no benefit in preventing AKI, reducing need for renal replacement therapy, or improving survival. Additionally, even at 'renal doses,' dopamine can cause significant tachycardia, arrhythmias, and immunosuppression (via DA2 receptors on lymphocytes), making it largely abandoned in clinical practice for this indication.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.