Clinician's Pocket Drug Reference 2008

Tables 241TABLE 11 (continued)Cytochrome P-450 Isoenzymes and Common DrugsThey Metabolize, Inhibit, and Induce aInhibitors:Inducers:Chemotherapy: Cyclophosphamide, erlotinib, ifosfamide,paclitaxel, tamoxifen, vinblastine, vincristineHIV protease inhibitors: Amprenavir, atazanavir, indinavir,nelfinavir, ritonavir, saquinavirHMG-CoA reductase inhibitors: Atorvastatin, lovastatin,simvastatinImmunosuppressive agents: Cyclosporine,tacrolimusMacrolide-type antibiotics: Clarithromycin, erythromycin,telithromycin, troleandomycinOpioids: Alfentanyl, cocaine, fentanyl, sufentanilSteroids: Budesonide, cortisol, 17--estradiol, progesteroneOthers: Acetaminophen, amiodarone, carbamazepine,delavirdine, efavirenz, nevirapine, quinidine, repaglinide,sildenafil, tadalafil, trazodone, vardenafilAmiodarone, amprenavir, atazanavir, ciprofloxacin, cisapride,clarithromycin, diltiazem, erythromycin, fluconazole,fluvoxamine, grapefruit juice (in high ingestion),indinavir, itraconazole, ketoconazole, nefazodone, nelfinavir,norfloxacin, ritonavir, telithromycin, troleandomycin,verapamil, voriconazoleCarbamazepine, efavirenz, glucocorticoids, macrolideantibiotics, nevirapine, phenytoin, phenobarbital, rifabutin,rifapentine, rifampin, St. John’s worta Increased or decreased (primarily hepatic cytochrome P-450) metabolism of medications may influence the effectivenessof drugs or result in significant drug-drug interactions. Understanding the common cytochromeP-450 isoforms (eg, CYP2C9, CYP2D9, CYP2C19, CYP3A4) and common drugs that are metabolized by (aka“substrates”), inhibit, or induce activity of the isoform helps minimize significant drug interactions. CYP3A is involvedin the metabolism of >50% of drugs metabolized by the liver.Based on data from Katzung B (ed): Basic and Clinical Pharmacology, 9th ed. McGraw-Hill, New York, 2004;The Medical Letter, Volume 47, July 4, 2004; http://www.fda.gov/cder/drug/drugreactions (accessed September16, 2006).