Statins Ritonavir

Clinically important, potentially hazardous interactions with cyclosporine, fenofibrate, gemfibrozil, HMG-CoA inhibitors (statins), ritonavir... 

Healthy volunteers were given protease inhibitors and statins, and the authors concluded that simvastatin should be avoided and that atorvastatin could be used with caution in people taking ritonavir and saquinavir (111). Dosage adjustment of pravastatin may be necessary with co-administration of ritonavir and saquinavir. Pravastatin does not alter the pharmacokinetics of nelfinavir, and thus appears to be safe for co-administration. 

Ajmaline, ajamlicine, flecainide, fluoxetine, isoniazid, ketoconazole, lobeline, nefazodone, paroxetine, (7 )-propaphenooe, quinidine, ritonavir, "statins," yohimbine, venlafaxine... 

In vitro studies found quinupristin/dalfopristin inhibited the cytochrome P450 isoenzyme CYP3A4-mediated metabolism of docetaxel, tamoxifen, and terfenadine. Quinupristin/dalfopristin is predicted to raise the levels of other drugs ineluding antiarrhythmics (disopyramide, lidocaine, quinidine), antiretrovirals (such as delavirdine, indinavir, nevirapine, ritonavir), astemizole, carbamazepine, cisapride, methyl-prednisolone, paclitaxel, statins (but see Lipid regulating drugs , (p.l086)), and vinca alkaloids. More study is needed. 

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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