Flashcards in CAM201 drugs used in shock Deck (9)
Dobutamine is a ß-agonist (beta 1 and 2 receptors).
Commonly used when treating shock
Increases cardiac output by increasing the inotropy
Classed as a sympathomimetic
Minor effect at α1 receptors, thus little effect on peripheral vascular resistance
Increases contractility and heart rate at ß1 receptors
Vasoconstricts by binding preferentially to α1 receptors in the vasculature smooth muscle.
Peripheral resistance is increased due to smooth muscle contraction, increasing BP and coronary artery blood flow.
Preferentially binds α2 and ß1 and ß2 receptors.
Particularly effective at increasing respiration rate in addition to contractility and heart rate
peptide hormone released from the pituitary gland
Induces vasoconstriction by activating V1 receptors on vascular smooth muscle, (a mechanism distinct from that of adrenergic vasoconstriction.)
Vasopressin vs. Noradrenaline
Several small trials suggested that vasopressin may represent a good alternative to norepinephrine or dopamine
VASST investigators showed no improvement in mortality rates with Vasopressin vs Noradrenaline
Low dose dopamine
Low dose (1 – 5 μg):
Binds D1 receptors (brain and kidney)," --> adenylate cyclase," --> cAMP" --> vasodilation at the renal artery bed
Improves renal function and prevents acute renal failure (the important effector organ in shock is the kidney).
The so called renal dose of dopamine is 2 μg/kg/min.
Medium dose doapoime
Medium Dose (5 – 15μg) binds D1 and ß1 receptors
Increases heart rate, while maintaining renal blood flow.
High dose dopamine
High Dose (> 15μg) acts on the α1 receptors ! increases vasoconstriction