Dopamine

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Summary

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Key Points

  • Mechanism
    • Adrenergic agonist
      • At intermediate doses, dopamine stimulates the beta-1 receptors in the heart, which increases heart rate and increases myocardial contractility
        • Positive inotrope and chronotrope
      • At high doses, dopamine also stimulates the alpha-adrenergic receptors which are located in the arteries, causing vasoconstriction, and thus increasing blood pressure
    • Clinical Use
      • Hypotension (e.g. shock)
        • Blood pressure is increased due to vasoconstriction, as well as stronger and faster contractions of the heart
        • If patient is hypovolemic, adequate fluid/blood product resuscitation is required prior to dopamine
      • (Symptomatic) Bradycardia
        • Second line drug, used when atropine is not effective
        • Heart rate is increased as a direct result of activation of the beta-1 receptors
      • Renal vasodilation
        • In very small doses, dopamine dilates the renal arteries, increasing urine output
    • Side Effects and Adverse Reactions
      • Tissue death (necrosis) around injection site
        • Due to drug-induced vasoconstriction causing poor tissue perfusion
        • Phentolamine is antidote for acute vasoconstriction, which should be injected into the site if extravasation occurs
      • Myocardial ischemia
        • Due to vasoconstrictive effects
      • Cardiac distress
        • Tachycardia, arrhythmias, palpitations may result due to dopamine’s effects on increasing HR
      • Nausea and vomiting
      • Do not run dopamine and bicarbonate in the same IV line, as bicarbonate inactivates dopamine