A 62-year-old woman in cardiogenic shock has blood pressure of 82/50 mmHg with a cardiac index of 1.7 L/min/m2. An inotrope that is a relatively selective beta-1 agonist with minimal chronotropic effect at therapeutic doses is chosen. Which drug is this?
- A Isoproterenol
- B Dobutamine ✓
- C Epinephrine
- D Norepinephrine
Correct answer: B. Dobutamine
Explanation
Dobutamine is a synthetic catecholamine acting mainly on beta-1 receptors, increasing contractility with comparatively less tachycardia than isoproterenol or epinephrine, making it suitable when a rise in heart rate would worsen myocardial oxygen demand. Isoproterenol is non-selective beta-1 and beta-2 and strongly chronotropic. Norepinephrine is predominantly alpha-1 with strong vasoconstriction. Epinephrine increases heart rate substantially and also produces beta-2-mediated vasodilation at low doses.
Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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