BNF for Children 2011-2012

BNFC 2011–2012 Appendix 1: Interactions 697Gabapentin (continued). Antidepressants: anticonvulsant effect of antiepilepticspossibly antagonised by MAOIs and .tricyclic-relatedantidepressants (convulsive threshold lowered); anticonvulsanteffect of antiepileptics antagonised by.SSRIs and .tricyclics (convulsive thresholdlowered); avoid concomitant use of antiepilepticswith .St John’s wort. 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 .orlistatGalantamine see ParasympathomimeticsGanciclovirNote Increased risk of myelosuppression with other myelosuppressivedrugs—consult product literatureNote Valganciclovir interactions as for ganciclovir. Antibacterials: increased risk of convulsions whenganciclovir given with .imipenem with cilastatin. Antivirals: ganciclovir possibly increases plasma concentrationof didanosine; avoidance of intravenousganciclovir advised by manufacturer of lamivudine;profound myelosuppression when ganciclovir givenwith .zidovudine (if possible avoid concomitantadministration, particularly during initial ganciclovirtherapy)Mycophenolate: plasma concentration of ganciclovirpossibly increased by mycophenolate, also plasmaconcentration of inactive metabolite of mycophenolatepossibly increasedProbenecid: excretion of ganciclovir reduced by probenecid(increased plasma concentration and risk oftoxicity)Tacrolimus: possible increased risk of nephrotoxicitywhen ganciclovir given with tacrolimusGefitinib. Antibacterials: plasma concentration of gefitinibreduced by .rifampicin—avoid concomitant use. Anticoagulants: gefitinib possibly enhances anticoagulanteffect of .warfarinAntidepressants: manufacturer of gefitinib advisesavoid concomitant use with St John’s wortAntiepileptics: manufacturer of gefitinib advises avoidconcomitant use with carbamazepine,phenobarbital and phenytoinAntifungals: plasma concentration of gefitinibincreased by itraconazole. Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis). Ulcer-healing Drugs: plasma concentration of gefitinibreduced by .ranitidineGemcitabineAnticoagulants: gemcitabine possibly enhances anticoagulanteffect of warfarin. Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis)Gemeprost see ProstaglandinsGemfibrozil see FibratesGentamicin see AminoglycosidesGestodene see ProgestogensGlibenclamide see AntidiabeticsGliclazide see AntidiabeticsGlimepiride see AntidiabeticsGlipizide see AntidiabeticsGlucosamine. Anticoagulants: glucosamine enhances anticoagulanteffect of .warfarin (avoid concomitant use)Glyceryl Trinitrate see NitratesGlycopyrronium see AntimuscarinicsGold see Sodium AurothiomalateGolimumab. Abatacept: avoid concomitant use of golimumab with.abataceptGolimumab (continued). Anakinra: avoid concomitant use of golimumab with.anakinra. Vaccines: avoid concomitant use of golimumab withlive .vaccines (see p. 599)Grapefruit Juice. Anti-arrhythmics: grapefruit juice increases plasmaconcentration of amiodarone; grapefruit juiceincreases plasma concentration of .dronedarone—avoid concomitant use. Antihistamines: grapefruit juice increases plasmaconcentration of .rupatadine—avoid concomitantuseAntimalarials: grapefruit juice possibly increasesplasma concentration of artemether/lumefantrineAntivirals: grapefruit juice possibly increases plasmaconcentration of efavirenzAnxiolytics and Hypnotics: grapefruit juice increasesplasma concentration of buspironeCalcium-channel Blockers: grapefruit juice possiblyincreases plasma concentration of amlodipine;grapefruit juice increases plasma concentration offelodipine, isradipine, lacidipine, lercanidipine, nicardipine,nifedipine, nimodipine and verapamil. Ciclosporin: grapefruit juice increases plasma concentrationof .ciclosporin (increased risk of toxicity). Colchicine: grapefruit juice possibly increases risk of.colchicine toxicity. Cytotoxics: avoidance of grapefruit juice advised bymanufacturer of everolimus, .lapatinib, .nilotinib and.pazopanib; grapefruit juice possibly increasesplasma concentration of vinflunine—manufacturer ofvinflunine advises avoid concomitant useIvabradine: grapefruit juice increases plasma concentrationof ivabradine. Lipid-regulating Drugs: grapefruit juice possiblyincreases plasma concentration of atorvastatin;grapefruit juice increases plasma concentration of.simvastatin—avoid concomitant use. Ranolazine: grapefruit juice possibly increases plasmaconcentration of .ranolazine—manufacturer ofranolazine advises avoid concomitant useSildenafil: grapefruit juice possibly increases plasmaconcentration of sildenafil. Sirolimus: grapefruit juice increases plasma concentrationof .sirolimus—avoid concomitant use. Tacrolimus: grapefruit juice increases plasma concentrationof .tacrolimusTadalafil: grapefruit juice possibly increases plasmaconcentration of tadalafil. Tolvaptan: grapefruit juice increases plasma concentrationof .tolvaptan—avoid concomitant use. Vardenafil: grapefruit juice possibly increases plasmaconcentration of .vardenafil—avoid concomitant useGriseofulvinAlcohol: griseofulvin possibly enhances effects ofalcohol. Anticoagulants: griseofulvin reduces anticoagulanteffect of .coumarinsAntiepileptics: absorption of griseofulvin reduced byphenobarbital (reduced effect)Ciclosporin: griseofulvin possibly reduces plasmaconcentration of ciclosporinOestrogens: anecdotal reports of contraceptive failureand menstrual irregularities when griseofulvin givenwith oestrogensProgestogens: anecdotal reports of contraceptivefailure and menstrual irregularities when griseofulvingiven with progestogensGuanethidine see Adrenergic Neurone BlockersHaloperidol see AntipsychoticsHalothane see Anaesthetics, GeneralHeparin see HeparinsHeparinsACE Inhibitors: increased risk of hyperkalaemia whenheparins given with ACE inhibitorsAliskiren: increased risk of hyperkalaemia whenheparins given with aliskirenAppendix 1: Interactions