Simvastatin should also be temporarily stopped if these antibacterials are required. Azithromycin does not inhibit CYP3A4 and, therefore, would not be expected to interact with simvastatin. Azithromycin does not inhibit CYP3A4 and, therefore, would not be expected to interact with simvastatin. Une bonne connaissance des mécanismes d'interaction et du métabolisme des médicaments permet une plus grande sécurité d'emploi. La prescription de statines non métabolisées par le CYP 3A4 semble préférable chez les patients polymédicamentés. Interacting drug or food Simvastatin prescribing advice Atorvastatin prescribing advice; Potent CYP3A4 inhibitors, including itraconazole, ketoconazole, erythromycin, clarithromycin, telithromycin. CONCLUSIONS: Macrolide antibiotics inhibit the metabolism of HMG-CoA reductase inhibitors that are metabolized by CYP3A4 (i.e., atorvastatin, cerivastatin, lovastatin, simvastatin). This interaction may result in myopathy and rhabdomyolysis, particularly in patients with renal insufficiency or those who are concurrently taking medications associated with myopathy. Find patient medical information for Simvastatin Oral on WebMD including its uses, side effects and safety, interactions, pictures, warnings and user ratings. From a practical viewpoint, given the relative unpredictability of the extent of the theophylline–macrolide interaction, it remains necessary to monitor serum theophylline concentrations whatever the macrolide being used, especially in those patients with baseline theophylline concentrations in the upper therapeutic range (15–20 mg l −1). This difference in the magnitude of the interaction effect is most likely due to the greater first-pass metabolism of lovastatin and simvastatin ( 95%) compared with atorvastatin (~85%). 4 Although atorvastatin is likely to have a lower risk of adverse interaction than lovastatin or simvastatin, it is not possible to declare it free of risk. Using a statin that is not a CYP3A4 substrate. macrolide antibiotics. Therefore, the average practice could potentially be exposing 1 per cent of its population to this inter - action each time they need an antibiotic. Most macrolides inhibit the cytochrome P450 isoenzyme CYP3A4, by which simvastatin and, to some extent, atorvastatin (Lipitor) are metabolised. Hence the concurrent use of a macrolide raises the levels of these statins. In an interaction study, a single dose of simvastatin 40mg was given to 12 healthy individuals. After 2 days of placebo or erythromycin (500mg three times daily), the plasma levels and AUC of simvastatin and its active metabolite were increased 6.2-fold and 3.9-fold respectively [19].