Dopamine and Dobutamine Induce Hypokalemia in Anesthetized Dogs

Summary: Epinephrine-induced hypokalemia appears to be mediated by β2-agonist activation of Na+/K+ ATPase. To determine whether dopamine and dobutamine induce hypokalemia, eight adult mongrel dogs were anesthetized and studied in random crossover fashion. Potassium [K+] was measured with an ion-selective microelectrode, and central hemodynamics were measured continuously. After stabilization, dopamine and dobutamine were infused at doses of 2, 4, 8, and 20 μg/kg/min (15-min increments/dose), and 0.9% NaCl was infused at equivalent volumes, with a 1-h washout between treatments. The mean change in [K+] at each infusion rate was compared between treatments among dogs with an adequate hemodynamic response. Among dopamine responders (n = 5), [K+] decreased from 3.74 ± 0.42 mEq/L at baseline to 3.63 ± 0.51 at 2 μg/kg/min (p < 0.02) and was not significantly different at higher doses. Among dobutamine responders (n = 7), [K+] decreased from 3.52 ± 0.74 at baseline to 3.31 ± 0.87 at 8 μg/kg/min (p < 0.02) and 3.25 ± 0.86 at 20 μg/kg/min (p < 0.02), and was not significantly different at lower doses. We conclude that dopamine and dobutamine induce significant hypokalemia, consistent with their adrenergic agonist activity, and this may be related to the known arrhythmogenicity of these agents.