BNF for Children 2011-2012

668 Appendix 1: Interactions BNFC 2011–2012Appendix 1: InteractionsAntifungals, Triazole. Antiepileptics (continued)increases plasma concentration of .phenytoin(consider reducing dose of phenytoin); voriconazoleincreases plasma concentration of.phenytoin, also phenytoin reduces plasma concentrationof voriconazole (increase dose ofvoriconazole and also monitor for phenytointoxicity); plasma concentration of posaconazolereduced by .phenytoin; plasma concentration ofitraconazole reduced by .phenytoin—avoid concomitantuseAntifungals: triazoles possibly antagonise effects ofamphotericin; plasma concentration of itraconazoleincreased by micafungin (consider reducing dose ofitraconazole). Antihistamines: itraconazole inhibits metabolism of.mizolastine—avoid concomitant use. Antimalarials: avoidance of triazoles advised bymanufacturer of .artemether/lumefantrineAntimuscarinics: avoidance of itraconazole advised bymanufacturer of darifenacin and tolterodine; manufacturerof fesoterodine advises dose reduction whenitraconazole given with fesoterodine—consult fesoterodineproduct literature; itraconazole increasesplasma concentration of solifenacin. Antipsychotics: itraconazole possibly increases plasmaconcentration of haloperidol; itraconazole possiblyinhibits metabolism of .aripiprazole (reduce dose ofaripiprazole); increased risk of ventricular arrhythmiaswhen triazoles given with .pimozide—avoidconcomitant use; triazoles possibly increase plasmaconcentration of quetiapine (reduce dose of quetiapine). Antivirals: posaconazole increases plasma concentrationof .atazanavir; plasma concentration ofitraconazole and posaconazole reduced by.efavirenz; plasma concentration of voriconazolereduced by .efavirenz, also plasma concentration ofefavirenz increased (increase voriconazole dose andreduce efavirenz dose); plasma concentration of bothdrugs may increase when itraconazole given withfosamprenavir; itraconazole increases plasma concentrationof .indinavir (consider reducing dose ofindinavir); plasma concentration of itraconazolepossibly reduced by nevirapine—consider increasingdose of itraconazole; fluconazole increases plasmaconcentration of .nevirapine, ritonavir and tipranavir;combination of itraconazole with .ritonavir mayincrease plasma concentration of either drug (orboth); plasma concentration of voriconazole reducedby .ritonavir—avoid concomitant use; triazolespossibly increase plasma concentration of saquinavir;fluconazole increases plasma concentration of.zidovudine (increased risk of toxicity). Anxiolytics and Hypnotics: itraconazole increasesplasma concentration of alprazolam; posaconazoleincreases plasma concentration of .midazolam;fluconazole and itraconazole increase plasma concentrationof .midazolam (risk of prolonged sedation);itraconazole increases plasma concentration ofbuspirone (reduce dose of buspirone). Bosentan: fluconazole possibly increases plasma concentrationof .bosentan—avoid concomitant use;itraconazole possibly increases plasma concentrationof bosentan. Calcium-channel Blockers: negative inotropic effectpossibly increased when itraconazole given withcalcium-channel blockers; itraconazole inhibitsmetabolism of .felodipine (increased plasma concentration);avoidance of itraconazole advised bymanufacturer of lercanidipine; itraconazole possiblyinhibits metabolism of dihydropyridines (increasedplasma concentration). Cardiac Glycosides: itraconazole increases plasmaconcentration of .digoxinAntifungals, Triazole (continued). Ciclosporin: fluconazole, itraconazole,posaconazole and voriconazole inhibit metabolism of.ciclosporin (increased plasma concentration). Clopidogrel: fluconazole, itraconazole and voriconazolepossibly reduce antiplatelet effect of.clopidogrel. Colchicine: itraconazole possibly increases risk of.colchicine toxicity—suspend or reduce dose ofcolchicine (avoid concomitant use in hepatic or renalimpairment)Corticosteroids: itraconazole possibly inhibits metabolismof corticosteroids and methylprednisolone;itraconazole increases plasma concentration ofinhaled budesonide. Cytotoxics: itraconazole inhibits metabolism of busulfan(increased risk of toxicity); itraconazole possiblyincreases side-effects of cyclophosphamide; itraconazole,posaconazole and voriconazole possiblyincrease plasma concentration of .everolimus—manufacturer of everolimus advises avoid concomitantuse; itraconazole increases plasma concentrationof gefitinib; avoidance of itraconazole,posaconazole and voriconazole advised by manufacturerof .lapatinib; avoidance of itraconazole andvoriconazole advised by manufacturer of .nilotinib;avoidance of itraconazole and voriconazole advisedby manufacturer of .pazopanib; posaconazole possiblyinhibits metabolism of .vinblastine and.vincristine (increased risk of neurotoxicity); itraconazolepossibly inhibits metabolism of.vincristine and .vinorelbine (increased risk ofneurotoxicity); itraconazole possibly increasesplasma concentration of .vinflunine—manufacturerof vinflunine advises avoid concomitant use. Diuretics: fluconazole increases plasma concentrationof eplerenone (reduce dose of eplerenone); itraconazoleincreases plasma concentration of.eplerenone—avoid concomitant use; plasma concentrationof fluconazole increased by hydrochlorothiazide. Ergot Alkaloids: increased risk of ergotism whentriazoles given with .ergotamine and methysergide—avoid concomitant use. 5HT 1 Agonists: itraconazole increases plasma concentrationof .eletriptan (risk of toxicity)—avoid concomitantuse. Ivabradine: fluconazole increases plasma concentrationof ivabradine—reduce initial dose of ivabradine;itraconazole possibly increases plasma concentrationof .ivabradine—avoid concomitant use. Lipid-regulating Drugs: possible increased risk ofmyopathy when triazoles given with atorvastatin;increased risk of myopathy when itraconazole orposaconazole given with .atorvastatin (avoid concomitantuse); fluconazole increases plasma concentrationof fluvastatin; increased risk of myopathywhen itraconazole or posaconazole given with.simvastatin (avoid concomitant use); possibleincreased risk of myopathy when voriconazole givenwith simvastatin; possible increased risk of myopathywhen fluconazole given with .simvastatin—avoidconcomitant useOestrogens: plasma concentration of voriconazoleincreased by oestrogensProgestogens: plasma concentration of voriconazolepossibly increased by progestogens. Ranolazine: itraconazole, posaconazole and voriconazolepossibly increase plasma concentration of.ranolazine—manufacturer of ranolazine advisesavoid concomitant useSildenafil: itraconazole increases plasma concentrationof sildenafil—reduce initial dose of sildenafil. Sirolimus: posaconazole possibly increases plasmaconcentration of sirolimus; itraconazole and voriconazoleincrease plasma concentration of .sirolimus—avoid concomitant use. Tacrolimus: fluconazole, itraconazole,posaconazole and voriconazole increase plasma