BNF for Children 2011-2012

BNFC 2011–2012 Appendix 1: Interactions 741Vigabatrin (continued). Antimalarials: possible increased risk of convulsionswhen antiepileptics given with chloroquine andhydroxychloroquine; anticonvulsant effect of antiepilepticsantagonised by .mefloquine. Antipsychotics: anticonvulsant effect of antiepilepticsantagonised by .antipsychotics (convulsive thresholdlowered). Orlistat: possible increased risk of convulsions whenantiepileptics given with .orlistatVildagliptin see AntidiabeticsVinblastine. Aldesleukin: avoidance of vinblastine advised bymanufacturer of .aldesleukin. Antibacterials: toxicity of vinblastine increased by.erythromycin—avoid concomitant use. Antifungals: metabolism of vinblastine possibly inhibitedby .posaconazole (increased risk of neurotoxicity). Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis)Antivirals: plasma concentration of vinblastine possiblyincreased by ritonavirVincristine. Antifungals: metabolism of vincristine possibly inhibitedby .itraconazole and .posaconazole (increasedrisk of neurotoxicity). Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis)Calcium-channel Blockers: metabolism of vincristinepossibly inhibited by nifedipineCardiac Glycosides: vincristine possibly reducesabsorption of digoxin tabletsVinflunine. Antibacterials: plasma concentration of vinfluninepossibly reduced by .rifampicin—manufacturer ofvinflunine advises avoid concomitant use. Antidepressants: plasma concentration of vinfluninepossibly reduced by .St John’s wort—manufacturerof vinflunine advises avoid concomitant use. Antifungals: plasma concentration of vinflunineincreased by .ketoconazole—manufacturer of vinflunineadvises avoid concomitant use; plasmaconcentration of vinflunine possibly increased by.itraconazole—manufacturer of vinflunine advisesavoid concomitant use. Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis). Antivirals: plasma concentration of vinflunine possiblyincreased by .ritonavir—manufacturer of vinflunineadvises avoid concomitant useGrapefruit Juice: plasma concentration of vinfluninepossibly increased by grapefruit juice—manufacturerof vinflunine advises avoid concomitant useVinorelbine. Antibacterials: possible increased risk of neutropeniawhen vinorelbine given with .clarithromycin. Antifungals: metabolism of vinorelbine possibly inhibitedby .itraconazole (increased risk of neurotoxicity). Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis)Vitamin A see VitaminsVitamin D see VitaminsVitamin E see VitaminsVitamin K (Phytomenadione) see VitaminsVitaminsAntibacterials: absorption of vitamin A possiblyreduced by neomycin. Anticoagulants: vitamin K antagonises anticoagulanteffect of .coumarins and .phenindione; vitamin Epossibly enhances anticoagulant effect of .coumarinsAntiepileptics: vitamin D requirements possiblyincreased when given with carbamazepine,phenobarbital or phenytoinAntifungals: plasma concentration of paricalcitol possiblyincreased by ketoconazoleAntivirals: increased risk of bleeding when high dosesof vitamin E given with tipranavirVitamins (continued)Ciclosporin: vitamin E possibly affects plasma concentrationof ciclosporinDiuretics: increased risk of hypercalcaemia whenvitamin D given with thiazides and related diureticsDopaminergics: pyridoxine reduces effects of levodopawhen given without dopa-decarboxylase inhibitorRetinoids: risk of hypervitaminosis A when vitamin Agiven with retinoidsSelenium: ascorbic acid possibly reduces absorption ofselenium (give at least 4 hours apart)Voriconazole see Antifungals, TriazoleWarfarin see CoumarinsXipamide see DiureticsXylometazoline see SympathomimeticsZafirlukast see Leukotriene Receptor AntagonistsZaleplon see Anxiolytics and HypnoticsZidovudineNote Increased risk of toxicity with nephrotoxic and myelosuppressivedrugs—for further details consult product literatureAnalgesics: increased risk of haematological toxicitywhen zidovudine given with NSAIDs; plasma concentrationof zidovudine possibly increased bymethadoneAntibacterials: absorption of zidovudine reduced byclarithromycin tablets (give at least 2 hours apart);manufacturer of zidovudine advises avoid concomitantuse with rifampicinAntiepileptics: zidovudine increases or decreasesplasma concentration of phenytoin; plasma concentrationof zidovudine possibly increased by valproate(increased risk of toxicity). Antifungals: plasma concentration of zidovudineincreased by .fluconazole (increased risk of toxicity)Antimalarials: increased antifolate effect when zidovudinegiven with pyrimethamine. Antivirals: profound myelosuppression when zidovudinegiven with .ganciclovir (if possible avoidconcomitant administration, particularly during initialganciclovir therapy); increased risk of anaemia whenzidovudine given with .ribavirin—avoid concomitantuse; zidovudine possibly inhibits effects of .stavudine(manufacturers advise avoid concomitant use);plasma concentration of zidovudine reduced by.tipranavirAtovaquone: metabolism of zidovudine possiblyinhibited by atovaquone (increased plasma concentration). Probenecid: excretion of zidovudine reduced by.probenecid (increased plasma concentration andrisk of toxicity)ZincAntibacterials: zinc reduces absorption of ciprofloxacin,levofloxacin, moxifloxacin, norfloxacin andofloxacin; zinc reduces absorption of tetracyclines,also absorption of zinc reduced by tetracyclinesCalcium Salts: absorption of zinc reduced by calciumsaltsEltrombopag: zinc possibly reduces absorption ofeltrombopag (give at least 4 hours apart)Iron: absorption of zinc reduced by oral iron, alsoabsorption of oral iron reduced by zincPenicillamine: absorption of zinc reduced by penicillamine,also absorption of penicillamine reduced byzincTrientine: absorption of zinc reduced by trientine, alsoabsorption of trientine reduced by zincZoledronic Acid see BisphosphonatesZolmitriptan see 5HT 1 AgonistsZolpidem see Anxiolytics and HypnoticsZonisamide. Antidepressants: anticonvulsant effect of antiepilepticspossibly antagonised by MAOIs and .tricyclic-relatedantidepressants (convulsive threshold lowered); anticonvulsanteffect of antiepileptics antagonised by.SSRIs and .tricyclics (convulsive thresholdAppendix 1: Interactions