Voriconazole Cimetidine

Drugs that affect voriconazole include the following barbiturates (long acting), cimetidine, nonnucleoside reverse transcriptase inhibitors (NNRIs), phenytoin, protease inhibitors, proton pump inhibitors, rifampin, rifabutin. 

Drugs that may inhibit cytochrome P450 metabolism of other drugs include amiodarone, androgens, atazanavir, chloramphenicol, cimetidine, ciprofloxacin, clarithromycin, cyclosporine, delavirdine, diltiazem, diphenhydramine, disulfiram, enoxacin, erythromycin, fluconazole, fluoxetine, fluvoxamine, furanocoumarins (substances in grapefruit juice), indinavir, isoniazid, itraconazole, ketoconazole, metronidazole, mexile-tine, miconazole, nefazodone, omeprazole, paroxetine, propoxyphene, quinidine, ritonavir, sulfamethizole, verapamil, voriconazole, zafirlukast, and zileuton. 

IFOSFAMIDE 1. ANTIBIOTICS -clarithromycin, erythromycin 2. ANTIFUNGALS -fluconazole, itraconazole, ketoconazole voriconazole 3. ANTIVIRALS-efavirenz, ritonavir 4. GRAPEFRUIT JUICE 5. H2 RECEPTOR BLOCKERS - cimetidine 1 plasma concentrations of 4-hydroxyifbsfamide, the active metabolite of ifosfamide, and risk of inadequate therapeutic response Due to inhibition of the isoenzymatic conversion to active metabolites Monitor the efficacy of ifosfamide clinically and t dose accordingly... 

IRINOTECAN 1. ANTIBIOTICS-clarithromycin, erythromycin 2. ANTICANCER AND IMMUNOMODULATING DRUGS - imatinib 3. ANTIFUNGALS -fluconazole, itraconazole, ketoconazole, voriconazole 4. ANTIVIRALS-efavirenz, ritonavir 5. GRAPEFRUIT JUICE 6. H2 RECEPTOR BLOCKERS - cimetidine t plasma concentrations of SN-38 (t AUC by 100%) and t toxicity of irinotecan, e.g. diarrhoea, acute cholinergic syndrome, interstitial pulmonary disease Due to inhibition of the metabolism of irinotecan by CYP3A4 isoenzymes by ketoconazole Peripheral blood counts should be checked before each course of treatment. Monitor lung function. Recommendation is to -L dose of irinotecan by 25%... 

The gastrointestinal absorption of ketoconazole is markedly reduced by cimetidine and ranitidine. The absorption of itraconazole is reduced (possibly halved) by H2-receptor antagonists, and, similarly, the absorption of posaconazole is reduced by about 40% by cimetidine. The absorption of fluconazole and voriconazole is not significantly affected by H2-receptor antagonists. 

A study in 12 healthy subjeets found that cimetidine 400 mg twice daily given with voriconazole 200 mg twice daily inereased the maximum plasma levels and AUC of voriconazole by about 20%, but this is not consid-... 

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