Macrolides Atorvastatin

MACROLIDES ATORVASTATIN, SIMVASTATIN Macrolides may T levels of atorvastatin and simvastatin the risk of myopathy t >1 Ox when erythromycin is co administered with a statin Macrolides inhibit CYP3A4-mediated metabolism of atorvastatin and simvastatin. Also, erythromycin and clarithromycin inhibit intestinal P-gp, which may t bioavailability of statins Avoid co-administration of macrolides with atorvastatin or simvastatin (temporarily stop the statin if the patient needs macrolide therapy). Manufacturers also recommend that patients are warned to look for the early signs of rhabdomyolysis when other statins are co-ingested with macrolides... 

The catabolism of lovastatin, simvastatin, and atorvastatin proceeds chiefly through CYP3A4, whereas that of fluvastatin and rosuvastatin is mediated by CYP2C9. Pravastatin is catabolized through other pathways, including sulfation. The 3A4-dependent reductase inhibitors tend to accumulate in plasma in the presence of drugs that inhibit or compete for the 3A4 cytochrome. These include the macrolide antibiotics, cyclosporine, ketoconazole and its congeners, HIVprotease inhibitors, tacrolimus, nefazodone, fibrates, and others (see Chapter 4). Concomitant use of reductase inhibitors with amiodarone or verapamil also causes an increased risk of myopathy. 

It seems probable that clarithromycin, erythromycin and troleandomycin, and to a lesser extent some of the other macrolides, slow the rate of metabolism of the carbamazepine by the cytochrome P450 isoenzyme CYP3A4 so that the anticonvulsant accumulates within the body." " Telithromycin is predicted to interact similarly." It was suggested that the carbamazepine toxicity seen with roxithromycin may have been mediated by P-glycoprotein inhibition, which occurred as a result of an interaction between roxithromycin and atorvastatin. 

Cases of acnte rhabdomyolysis have been reported between lovas-tatin and azithromycin, clarithromycin, or erythromycin and between simvastatin and clarithromycin or roxithromycin. Macrolide antibacterials have also been potentially implicated in cases of rhabdomyolysis with atorvastatin and pravastatin. Pharmacokinetic stndies sn est that the macrolides increase the levels of the statins metabolised by CYP3A4 (namely atorvastatin, Iovastatin and simvastatin). 

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