Classify the commonly used inotropic agents and describe their mechanism of action.

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College Answer

This question required a classification based on chemical structure and class action. 
Sympathomimetics, phosphodiesterase inhibitors, calcium sensitizers and cardiac 
glycosides should have been mentioned. Additional detail was expected, 
subdividing Sympathomimetics into catecholamines (naturally occurring and 
synthetic), and non-catecholamines (direct and indirect acting). Further classification 
based on peripheral vasomotor action demonstrated greater understanding

Better answers included diagrams illustrating the mechanism and point of action on 
the cardiac myocyte. Discussion of receptors, second messengers, and the role of 
calcium was essential.
The question was aimed at “commonly used” agents, although some marks were 
awarded for discussion of calcium, glucagon and other rarely used drugs. 
Insufficient detail regarding mechanisms of action was a common observation.
Syllabus: C2d 2
References: Pharmacology and Physiology in Anaesthetic Practice, Stoelting 4th Ed 
p293-320. Basic and Clinical Pharmacology Katzung 10th Ed p121-198.
Pharmacology Rang & Dale 6th Ed p168-187, 290-291