Rosuvastatin Fibrates

Fibrates are being combined with statins to expand their potential in the dyslipidemia market. A recent clinical study examined the effects of rosuvastatin (10) and fenofibrate as mono and combination therapy in hyperlipidemic diabetic patients [43]. In late 2006, large scale Phase III clinical trials of rosuvastatin in combination with a next-generation fibrate, ABT 335, were initiated for evaluation of safety and efficacy in patients with mixed dyslipidemia. 

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. 

Rare adverse effects of fibrates include rashes, gastrointestinal symptoms, myopathy, arrhythmias, hypokalemia, and high blood levels of aminotransferases or alkaline phosphatase. A few patients show decreases in white blood count or hematocrit. Both agents potentiate the action of coumarin and indanedione anticoagulants, and doses of these agents should be adjusted. Rhabdomyolysis has occurred rarely. Risk of myopathy increases when fibrates are given with reductase inhibitors. The use of fenofibrate with rosuvastatin appears to minimize this risk. Fibrates should be avoided in patients with hepatic or renal dysfunction. There appears to be a modest increase in the risk of cholesterol gallstones. 

FIBRATES STATINS Gemfibrozil may t atorvastatin, rosuvastatin and simvastatin levels (risk of myopathy with simvastatin) Uncertain Avoid co-administration of simvastatin and gemfibrozil. When using other statins, warn patients to watch for the features of myopathy... 

In addition to these newer agents, there are currently three fibrate-based combinations with HMG-CoA reductase inhibitors in clinical trials. In phase III, Sciele has fenofibrate/pravastatin combination and AstraZeneca and Abbott have rosuvastatin/choline fenofibrate (ABT335), while in phase II, Life Cycle Pharma have atorvastatin / fenofibrate. 

The plasma levels of lovastatin, simvastatin, atorvastatin and pravastatin are increased by gemfibrozil, the levels of fluvastatin are increased by bezaflbrate, and the levels of pravastatin are increased by fenoflbrate. No pharmacokinetic interactions occur with the combinations of fluvastatin with gemfibrozil, lovastatin with bezaflbrate, and pravastatin, rosuvastatin or simvastatin with fenoflbrate. Both statins and fibrates are known to cause rhabdomyolysis, and their concurrent use increases the risk of this reaction. 

Prueksaritanont, T. Tang, C. (Jiu, Y. Mu, L. Subramanian, R. Lin, J.H. Effects of fibrates on metabolism of statins in human hepatocytes, Drug Metab.Dispos., 2002, 30, 1280-1287. [cerivastatin simvastatin atorvastatin rosuvastatin pravastatin]... 

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