At what dose does dopamine exhibit β1 and β2 agonist activity?

Dopamine exhibits β1 and β2 agonist activity at medium doses, which are typically in the range of 5 to 10 micrograms per kilogram per minute. At this dosage, dopamine stimulates β1 adrenergic receptors, leading to increased heart rate and contractility, which is particularly useful in treating conditions such as heart failure. Additionally, β2 agonist activity can contribute to vasodilation, affecting peripheral circulation.

At lower doses (generally less than 5 micrograms per kilogram per minute), dopamine primarily acts on renal dopaminergic receptors, promoting renal blood flow and diuresis rather than significant cardiac stimulation. Conversely, at higher doses (above 10 micrograms per kilogram per minute), dopamine begins to exhibit α-adrenergic effects, resulting in vasoconstriction rather than β mediated effects.

Understanding the dose-dependent action of dopamine is crucial, especially in critical care settings where precise dosing can significantly influence hemodynamic outcomes.