Compare and contrast the pharmacology of midazolam and dexmedetomidine when used for sedation.
This question was also well suited to be answered in a preset format. For example a tabular
format that had headings such as mechanism of action, preparations, dosing,
pharmacokinetics, metabolism and excretion, pharmacodynamics, drug interactions and side
A good answer was expected to include the following points. Under mechanism of action,
mention that both drugs produce sedation by hyperpolarizing CNS nerve membranes and act
on different receptors (Midazolam binds the benzodiazepine receptor and dexmedetomidine
being selective for the a2 receptor). Also mention of other effects for each drug, eg
anxiolytic, anticonvulsunt, analgesia, etc. A similar approach would be required for other key
areas such as metabolism and excretion,(including alterations with age, organ failure, disease,
etc), drug interactions, pharmacodynamics, particularly in relation to important physiological
effects (eg CNS and CVS effects).
A brief summary of the similarities and differences which influence the clinical use of these
agents gained more marks and showed the candidate had applied knowledge of these drugs.
The common omissions were lack of explanation of mechanism of action and failure to
mention pharmacodynamic effects, drug interactions and specific advantages for each agent.