ACLS Drugs – Dopamine

Dosing

Because dopamine’s mechanism of action changes as the dose increases, we look at dosing and pharmacology concurrently.

First, dopamine’s dosing range is 2–20 mcg/kg/min. Dopamine is always administered mcg/kg/min. 2 mcg/kg/min is usually considered a renal dose to dilate the mesenteric arterial system and help with renal kidney perfusion.

Dopamine’s dosing range is between 2–20 mcg/kg/min.

Dopamine Dosing at 5–10 mcg/kg/min

Once we move to 5 mcg/kg/min and 10 mcg/kg/min, the mechanism of action is predominately beta1 (β1) in the heart. Five is a magic number with dopamine infusion, and we’ll talk more of it later. Beta increases the rate of heart contractility, which means dopamine acts as a positive chronotrope. Beta also increases the force of contractility, which means dopamine acts as a positive inotrope. Overall, when dopamine is administered between 5 and 10 mcg/kg/min, the effect is predominately beta.

Dopamine primarily stimulates beta receptors when administered between 5 and 10 mcg/kg/min.

Dopamine Dosing at 15–20 mcg/kg/min

We begin to see the alpha1 (α1) effect activate at the 15–20 mcg/kg/min range. The alpha effect is peripheral vasoconstriction in the vessels. Dopamine now acts as a vasopressor, causing vasoconstriction to raise the blood pressure.

The golden rule “fluids before pressors” now comes into play. If you are causing vasoconstriction and your patient is volume depleted, there is nothing to press. You can’t raise any blood pressure because there is nothing “in the tank.” Remember to give fluids before vasopressors.

Related Video – What are Intravenous (IV) Fluids?

Importantly, as we pass the 10 mcg/kg/min range, we are not lessening any of dopamine’s beta effects. We’re simply adding alpha effects.

Between 15 and 20 mcg/kg/min, dopamine stimulates alpha receptors, producing alpha effects.

Indications

Dopamine is the second drug of choice in the bradycardia algorithm if atropine is ineffective. Remember, if you’re administering dopamine to raise the heart rate, you want those beta effects which occur somewhere between 5 and 10 mcg/kg/min.

Past that, you’ll move into alpha vasopressor effects, which may not raise the heart rate, especially in bradycardic patients because the problem is low heart rate. You’ll also find dopamine in any algorithm where hypotension is a factor.

Other Considerations

Dopamine has varying concentration levels. It may be administered at 400 mg in 250 mL with a concentration of  1600 mcg/mL. Be careful in the ICU because some patients may be on an 800 mg per 250mL concentration of dopamine. These are often patients with heart failure, and they cannot tolerate that extra fluid. You must know the exact concentration before switching the patient over to your pumps for transport.

A dopamine concentration of 1600 mcg/mL.

Dopamine concentration of 3200 mcg/mL, which may be used for patients with heart failure.

Summary

Dopamine’s mechanism of action changes as the dose increases. At lower doses in the 5–10 mcg/kg/min range, you’ll see dopamine’s beta effects. At doses of 15–20 mcg/kg/min, you’ll also see its alpha effects. Physicians must know the exact concentration of dopamine a patient requires.