Saquinavir Eplerenone

This approach can be easily reproduced with other CYP3A-sensitive substrates, such as buspirone, triazolam, and eplerenone, and yields quantitative examination of the relationship between these sensitive substrates and midazolam. This question was pursued in some depth by Ragueneau-Majlessi et al. (22) and showed that classification of inhibitors (five moderate and eight potent) was substrate independent in 74% to 83% of the instances. Exceptions pertained to buspirone and simvastatin that seemed to be systematically more sensitive than midazolam and saquinavir that appeared less sensitive (22). Furthermore, results of this analysis allow an extrapolation of the inhibitory effect of a compound from one probe to another avoiding a duplication of studies (i.e., effects of inhibitor on simvastatin calculated from its effect on midazolam). 

POTASSIUM-SPARING DIURETICS ANTIVIRALS-PROTEASE INHIBITORS Possibly t adverse effects of eplerenone with nelfinavir, ritonavir (with or without lopinavir) and saquinavir Inhibition of CYP3A4-mediated metabolism of eplerenone Avoid concomitant use... 

Eplerenone reduced the maximum level of saquinavir by 30%, and the AUC by 21%, but the clinical relevance of this has not been assessed. 

In the UK, the manufacturers recommend that the dose of eplerenone should not exceed 25 mg daily in patients taking mild to moderate CYP3A4 inhibitors such as amiodarone, diltiazem, erythromycin, fluconazole, saquinavir and verapamil. In the US, the manufacturer recommends that the starting dose for hypertension should be reduced to 25 mg daily for patients taking these drugs. This seems a sensible precaution. However, note that in many cases erythromycin appears to be a more potent inhibitor of CYP3A4 than clarithromycin (and certainly the other moderate CYP3A4 inhibitors listed above), and so extra caution is probably warranted with this combination. 

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