BNF for Children 2011-2012

672 Appendix 1: Interactions BNFC 2011–2012Appendix 1: InteractionsAntipsychotics. Diuretics (continued).diuretics; risk of ventricular arrhythmias withpimozide increased by hypokalaemia caused by.diuretics (avoid concomitant use); enhanced hypotensiveeffect when phenothiazines given with diureticsDopaminergics: increased risk of extrapyramidal sideeffectswhen antipsychotics given with amantadine;antipsychotics antagonise effects of apomorphine,levodopa and pergolide; antipsychotics antagonisehypoprolactinaemic and antiparkinsonian effects ofbromocriptine and cabergoline; manufacturer ofamisulpride advises avoid concomitant use of levodopa(antagonism of effect); avoidance of antipsychoticsadvised by manufacturer of pramipexole,ropinirole and rotigotine (antagonism of effect)Histamine: antipsychotics theoretically antagoniseeffects of histamine—manufacturer of histamineadvises avoid concomitant use. Hormone Antagonists: manufacturer of droperidoladvises avoid concomitant use with .tamoxifen (riskof ventricular arrhythmias). Ivabradine: increased risk of ventricular arrhythmiaswhen pimozide given with .ivabradineLithium: increased risk of extrapyramidal side-effectsand possibly neurotoxicity when clozapine, flupentixol,haloperidol, phenothiazines or zuclopenthixolgiven with lithium; possible risk of toxicity whenolanzapine given with lithium; increased risk ofextrapyramidal side-effects when sulpiride given withlithiumMemantine: effects of antipsychotics possibly reducedby memantineMethyldopa: enhanced hypotensive effect when antipsychoticsgiven with methyldopa (also increasedrisk of extrapyramidal effects)Metoclopramide: increased risk of extrapyramidalside-effects when antipsychotics given with metoclopramideMoxonidine: enhanced hypotensive effect whenphenothiazines given with moxonidineMuscle Relaxants: promazine possibly enhanceseffects of suxamethoniumNitrates: enhanced hypotensive effect when phenothiazinesgiven with nitrates. Penicillamine: avoid concomitant use of clozapine with.penicillamine (increased risk of agranulocytosis). Pentamidine Isetionate: increased risk of ventriculararrhythmias when amisulpride or droperidol givenwith .pentamidine isetionate—avoid concomitantuse; increased risk of ventricular arrhythmias whenphenothiazines given with .pentamidine isetionateSodium Benzoate: haloperidol possibly reduces effectsof sodium benzoateSodium Oxybate: antipsychotics possibly enhanceeffects of sodium oxybateSodium Phenylbutyrate: haloperidol possibly reduceseffects of sodium phenylbutyrateSympathomimetics: antipsychotics antagonise hypertensiveeffect of sympathomimetics; antipsychoticeffects of chlorpromazine possibly antagonised bydexamfetamine; side-effects of risperidone possiblyincreased by methylphenidate. Tacrolimus: manufacturer of droperidol advises avoidconcomitant use with .tacrolimus (risk of ventriculararrhythmias)Tetrabenazine: increased risk of extrapyramidal sideeffectswhen antipsychotics given with tetrabenazineUlcer-healing Drugs: effects of antipsychotics,chlorpromazine and clozapine possibly enhanced bycimetidine; plasma concentration of clozapine possiblyreduced by omeprazole; absorption of sulpiridereduced by sucralfateVasodilator Antihypertensives: enhanced hypotensiveeffect when phenothiazines given with hydralazine,minoxidil or sodium nitroprussideAntivirals see Abacavir, Aciclovir, Adefovir, Atazanavir,Cidofovir, Darunavir, Didanosine, Efavirenz, Emtricitabine,Etravirine, Famciclovir, Fosamprenavir,Foscarnet, Ganciclovir, Indinavir, Lamivudine, Lopinavir,Maraviroc, Nelfinavir, Nevirapine, Raltegravir,Ribavirin, Ritonavir, Saquinavir, Stavudine, Telbivudine,Tenofovir, Tipranavir, Valaciclovir, and ZidovudineAnxiolytics and HypnoticsACE Inhibitors: enhanced hypotensive effect whenanxiolytics and hypnotics given with ACE inhibitorsAdrenergic Neurone Blockers: enhanced hypotensiveeffect when anxiolytics and hypnotics given withadrenergic neurone blockersAlcohol: increased sedative effect when anxiolytics andhypnotics given with alcoholAlpha-blockers: enhanced hypotensive and sedativeeffects when anxiolytics and hypnotics given withalpha-blockersAnaesthetics, General: increased sedative effect whenanxiolytics and hypnotics given with general anaestheticsAnalgesics: metabolism of midazolam possibly inhibitedby fentanyl; increased sedative effect whenanxiolytics and hypnotics given with opioid analgesicsAngiotensin-II Receptor Antagonists: enhancedhypotensive effect when anxiolytics and hypnoticsgiven with angiotensin-II receptor antagonists. Antibacterials: metabolism of midazolam inhibited by.clarithromycin, .erythromycin and .telithromycin(increased plasma concentration with increasedsedation); plasma concentration of buspironeincreased by erythromycin (reduce dose of buspirone);metabolism of zopiclone inhibited by erythromycin;metabolism of benzodiazepines possiblyaccelerated by rifampicin (reduced plasma concentration);metabolism of diazepam accelerated byrifampicin (reduced plasma concentration); metabolismof buspirone and zaleplon possibly acceleratedby rifampicin; metabolism of zolpidem accelerated byrifampicin (reduced plasma concentration andreduced effect); plasma concentration of zopiclonesignificantly reduced by rifampicin; metabolism ofdiazepam inhibited by isoniazidAnticoagulants: chloral may transiently enhance anticoagulanteffect of coumarins. Antidepressants: plasma concentration of alprazolamincreased by fluoxetine; plasma concentration ofmelatonin increased by .fluvoxamine—avoid concomitantuse; plasma concentration of some benzodiazepinesincreased by fluvoxamine; sedative effectspossibly increased when zolpidem given with sertraline;manufacturer of buspirone advises avoid concomitantuse with MAOIs; avoidance of buspirone for10 days after stopping tranylcypromine advised bymanufacturer of tranylcypromine; plasma concentrationof oral midazolam possibly reduced by StJohn’s wort; increased sedative effect when anxiolyticsand hypnotics given with mirtazapine, tricyclicrelatedantidepressants or tricyclicsAntiepileptics: plasma concentration of midazolamreduced by carbamazepine; plasma concentration ofclonazepam often reduced by carbamazepine,phenobarbital and phenytoin; benzodiazepines possiblyincrease or decrease plasma concentration ofphenytoin; diazepam increases or decreases plasmaconcentration of phenytoin; plasma concentration ofclobazam increased by stiripentol; clobazam possiblyincreases plasma concentration of valproate; plasmaconcentration of diazepam and lorazepam possiblyincreased by valproate; increased risk of side-effectswhen clonazepam given with valproate. Antifungals: plasma concentration of alprazolamincreased by itraconazole and ketoconazole; plasmaconcentration of midazolam increased by.fluconazole, .itraconazole and .ketoconazole (riskof prolonged sedation); plasma concentration ofbuspirone increased by itraconazole (reduce dose ofbuspirone); plasma concentration of midazolamincreased by .posaconazole