What is the antidote for dopamine?

Appeared in: DSSSB 14 August 2024

Explanation

Phentolamine is the correct antidote for dopamine extravasation.
Dopamine's vasoconstrictive effects at high doses are mediated by alpha-1 adrenergic receptors.
Phentolamine is an alpha-adrenergic antagonist (alpha-blocker) that directly counteracts this effect.
By blocking the alpha-1 receptors, phentolamine reverses the localized vasoconstriction caused by extravasated dopamine.
This action restores blood flow to the ischemic tissue, preventing necrosis and further damage.

Option A: Dobutamine is primarily a beta-1 adrenergic agonist. It increases cardiac contractility but does not block the alpha-receptor-mediated vasoconstriction caused by dopamine.
Option C: Epinephrine is a potent agonist of both alpha and beta-adrenergic receptors. Administering it would worsen the vasoconstriction and tissue ischemia.
Option D: Norepinephrine is another potent vasoconstrictor that acts predominantly on alpha-adrenergic receptors. It would exacerbate the tissue injury.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Antidote for vasopressor (dopamine) extravasation as background academic context rather than a clinical decision trigger.
Nurses administering vasopressors like dopamine must frequently assess the IV site for signs of extravasation, such as pain, swelling, blanching, and coolness.
Prompt recognition and immediate intervention are critical to prevent severe complications like tissue necrosis, ulceration, and the need for surgical debridement or amputation.
Every nurse working in a critical care setting should know the immediate steps for managing vasopressor extravasation: stop the infusion, leave the cannula in place initially, attempt to aspirate the drug, and notify the physician immediately for orders to administer the antidote.

How to Approach the Question

First, identify the core of the question, which is asking for the 'antidote' for 'dopamine'.
Recall the pharmacological class of dopamine. It is a catecholamine and a vasopressor with dose-dependent receptor activity (dopaminergic, beta-1, alpha-1).
Consider the most dangerous adverse effect that would require a specific antidote. For potent vasopressors, this is extravasation leading to tissue necrosis from intense vasoconstriction.
This vasoconstriction is an alpha-adrenergic effect. Therefore, the antidote must be an alpha-adrenergic antagonist (an alpha-blocker).
Evaluate the options: Dobutamine, Epinephrine, and Norepinephrine are all adrenergic agonists (sympathomimetics) and would not reverse the effect. Phentolamine is the only alpha-blocker in the list.
Conclude that Phentolamine is the correct choice as it directly antagonizes the mechanism of injury.

Concept Tested & Keywords

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E6 Pharmacology Nursing Lilley 11e Part 1 pp. 318-320, 317-319

Practise the full DSSSB 14 August 2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.