Compare the pharmacology of piperacillin-tazobactam and ciprofloxacin.

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College Answer

This question was most effectively answered using a tabular format. Only a minority of candidates demonstrated a comprehensive knowledge of these level 1 drugs and very few candidates compared the two in areas which lent themselves to comparison. The spectrum of activity generally lacked detail. Few candidates mentioned that piperacillin-tazobactam had superior gram-positive cover, both have extensive gram-negative cover including Pseudomonas. Piperacillin-tazobactam is effective against anaerobes; whilst ciprofloxacin has some atypical cover against Mycoplasma.

The mechanism of action was generally well described for piperacillin; many candidates incorrectly stated the mechanism of action for ciprofloxacin, confusing the drug with a macrolide. Better answers included time- dependant and concentration-dependent killing. The concept of half-life was frequently confused with the dosing interval.

Minimal marks were awarded for “allergy” and “gastrointestinal side-effects”. Better candidates mentioned Liver function derangement, neutropenia, interstitial nephritis for piperacillin and tendonitis for ciprofloxacin