Lipid - regulating drugs simvastatin

The protease inhibitors, especially ritonavir, are known to be strong inhibitors of the cytochrome P450 isoenzyme CYP3A4. The levels of statins metabolised by this isoenzyme (notably simvastatin, and to some extent atorvastatin) are therefore increased. See Lipid regulating drugs , (p.l086) for information on the metabolism of the individual statins. 

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