Question 23

Compare and contrast the mechanism of action, spectrum of activity and adverse effects of benzyl penicillin and fluconazole.

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College Answer

To pass this question each of the three components needed to be compared and contrasted 
for both agents. A tabulated answer helped in this regard but was not essential.
Some answers included information that could not gain marks, as it was not directly relevant to 
the question asked (e.g. presentation and dose).
In spectrum of activity, as well as what important organisms the agents were effective against, 
marks were also given for the important organisms that they were not effective against (e.g. 
MRSA and beta-lactamase producing organisms for penicillin G; and aspergillus for 
In general, of the two agents, fluconazole was the least well answered. For example, a 
common omission either in mechanism of action or in adverse effects was that fluconazole 
inhibits microsomal P450 enzymes. 
Some candidates confused fluoroquinalone with fluconazole