Macrolides and Cyclosporine Use

[Volvulus10]

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Hey everyone,

I just received the 2014 edition of "Step Up to STEP 1" book and it actually looks pretty awesome as a side resource to First Aid. In the introduction (page 4), it shows an example of the testing interface which has the following question...

A 45 year old man has just undergone a successful heart transplant for dilated cardiomyopathy and has been placed on cyclosporine as an immunosuppressive agent. Three weeks later he develops cough, chest pain, and intermittent fevers and is diagnosed w/ a right upper lobe pneumonia. Which antibiotic would be best to avoid a state of cyclosporine toxicity

A: Erythromycin
B: Azithromycin
C: Clarithromycin
D: Ciprofloxacin
E: Norfloxacin

The only thing First Aid has on this is that aminoglycosides (gentamicin, streptomycin) should be avoided w/ cyclosporine use, not fluoroquinolones or macrolides.

Anyone know the answer?

 

[Missorleans]

Macrolides are P450 inhibitors, erythromycin is worse about this than azithromycin, IIRC. However, FA says cipro is also a P450 inhibitor, so I'm not really sure what the best answer is.

 

[Bertram Lupov]

Interesting. RUL pneumonia screams K. pneumonia at me. Missorleans is right, macrolides are P450 inhibitors, but they're more useful with atypicals and don't cover KP. So, for me, that would narrow the answer down to the two f'quinolones. I would go with norfloxacin, given cipro's P450 inhibitor activity.

What does everyone else think?

 

[Transposony]

I don't think it's a real question since all except Azithromycin should be avoided in a patient on cyclosporine.
The question should have been "Which antibiotic would be best used to avoid a state of cyclosporine toxicity".