BNF for Children 2011-2012

BNFC 2011–2012 Appendix 1: Interactions 699Homatropine see AntimuscarinicsHormone Antagonists see Bicalutamide, Danazol,Dutasteride, Exemestane, Flutamide, Lanreotide,Octreotide, Tamoxifen, Toremifene, and Trilostane5HT 1 Agonists. Antibacterials: plasma concentration of eletriptanincreased by .clarithromycin and .erythromycin (riskof toxicity)—avoid concomitant use; metabolism ofzolmitriptan possibly inhibited by quinolones (reducedose of zolmitriptan). Antidepressants: increased risk of CNS toxicity whensumatriptan given with .citalopram, .escitalopram,.fluoxetine, .fluvoxamine or .paroxetine; metabolismof frovatriptan inhibited by fluvoxamine;metabolism of zolmitriptan possibly inhibited byfluvoxamine (reduce dose of zolmitriptan); CNStoxicity reported when sumatriptan given with sertraline;possible increased serotonergic effects when5HT 1 agonists given with duloxetine or venlafaxine;increased risk of CNS toxicity when zolmitriptangiven with .MAOIs; risk of CNS toxicity whenrizatriptan or sumatriptan given with .MAOIs (avoidrizatriptan or sumatriptan for 2 weeks after MAOIs);risk of CNS toxicity when rizatriptan or sumatriptangiven with .moclobemide (avoid rizatriptan orsumatriptan for 2 weeks after moclobemide); risk ofCNS toxicity when zolmitriptan given with.moclobemide (reduce dose of zolmitriptan);increased serotonergic effects when 5HT 1 agonistsgiven with .St John’s wort—avoid concomitant use. Antifungals: plasma concentration of eletriptanincreased by .itraconazole and .ketoconazole (risk oftoxicity)—avoid concomitant use; plasma concentrationof almotriptan increased by ketoconazole(increased risk of toxicity). Antivirals: plasma concentration of eletriptan increasedby .indinavir, .nelfinavir and .ritonavir (risk oftoxicity)—avoid concomitant useBeta-blockers: plasma concentration of rizatriptanincreased by propranolol (manufacturer of rizatriptanadvises halve dose and avoid within 2 hours ofpropranolol)Dopaminergics: avoidance of 5HT 1 agonists advisedby manufacturer of selegiline. Ergot Alkaloids: increased risk of vasospasm wheneletriptan, frovatriptan or naratriptan given with.ergotamine and methysergide (avoid ergotamineand methysergide for 24 hours after eletriptan,frovatriptan or naratriptan, avoid eletriptan,frovatriptan or naratriptan for 24 hours after ergotamineand methysergide); increased risk of vasospasmwhen almotriptan, rizatriptan, sumatriptan orzolmitriptan given with .ergotamine and methysergide(avoid ergotamine and methysergide for 6hours after almotriptan, rizatriptan, sumatriptan orzolmitriptan, avoid almotriptan, rizatriptan,sumatriptan or zolmitriptan for 24 hours after ergotamineand methysergide)Lithium: possible risk of toxicity when sumatriptangiven with lithiumUlcer-healing Drugs: metabolism of zolmitriptaninhibited by cimetidine (reduce dose of zolmitriptan)5HT 3 AntagonistsAnalgesics: ondansetron possibly antagonises effectsof tramadolAntibacterials: metabolism of ondansetron acceleratedby rifampicin (reduced effect)Antiepileptics: metabolism of ondansetron acceleratedby carbamazepine and phenytoin (reduced effect)Hydralazine see Vasodilator AntihypertensivesHydrochlorothiazide see DiureticsHydrocortisone see CorticosteroidsHydroflumethiazide see DiureticsHydromorphone see Opioid AnalgesicsHydrotalcite see AntacidsHydroxocobalaminAntibacterials: response to hydroxocobalamin reducedby chloramphenicolHydroxycarbamide. Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis). Antivirals: increased risk of toxicity when hydroxycarbamidegiven with .didanosine and .stavudine—avoid concomitant useHydroxychloroquine see Chloroquine and HydroxychloroquineHydroxyzine see AntihistaminesHyoscine see AntimuscarinicsIbandronic Acid see BisphosphonatesIbuprofen see NSAIDsIdarubicin. Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis). Ciclosporin: plasma concentration of idarubicinincreased by .ciclosporinIfosfamide. Anticoagulants: ifosfamide possibly enhances anticoagulanteffect of .coumarins. Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis)Cytotoxics: increased risk of otoxicity when ifosfamidegiven with cisplatinIloprostAnalgesics: increased risk of bleeding when iloprostgiven with NSAIDs or aspirinAnticoagulants: iloprost possibly enhances anticoagulanteffect of coumarins and heparins;increased risk of bleeding when iloprost given withphenindioneClopidogrel: increased risk of bleeding when iloprostgiven with clopidogrelEptifibatide: increased risk of bleeding when iloprostgiven with eptifibatideTirofiban: increased risk of bleeding when iloprostgiven with tirofibanImatinibAnalgesics: manufacturer of imatinib advises cautionwith paracetamol. Antibacterials: plasma concentration of imatinibreduced by .rifampicin—avoid concomitant useAnticoagulants: manufacturer of imatinib advisesreplacement of warfarin with a heparin (possibility ofenhanced warfarin effect). Antidepressants: plasma concentration of imatinibreduced by .St John’s wort—avoid concomitant use. Antiepileptics: plasma concentration of imatinibreduced by .carbamazepine, .oxcarbazepine and.phenytoin—avoid concomitant useAntifungals: plasma concentration of imatinibincreased by ketoconazole. Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis)Ciclosporin: imatinib possibly increases plasma concentrationof ciclosporinLipid-regulating Drugs: imatinib increases plasmaconcentration of simvastatinThyroid Hormones: imatinib possibly reduces plasmaconcentration of levothyroxineImidapril see ACE InhibitorsImipenem with Cilastatin. Antiepileptics: carbapenems reduce plasma concentrationof .valproate—avoid concomitant use. Antivirals: increased risk of convulsions when imipenemwith cilastatin given with .ganciclovirVaccines: antibacterials inactivate oral typhoidvaccine—see p. 620Imipramine see Antidepressants, TricyclicImmunoglobulinsNote For advice on immunoglobulins and live virus vaccines,see under Normal Immunoglobulin, p. 622Indacaterol see Sympathomimetics, Beta 2Indapamide see DiureticsIndinavirAldesleukin: plasma concentration of indinavir possiblyincreased by aldesleukinAppendix 1: Interactions