BNF for Children 2011-2012

BNFC 2011–2012 Appendix 1: Interactions 705Macrolides. Antivirals (continued)tration of azithromycin increased by nelfinavir(increased risk of toxicity); plasma concentrationof clarithromycin reduced by nevirapine (butconcentration of an active metabolite increased),also plasma concentration of nevirapineincreased; plasma concentration of clarithromycinincreased by .ritonavir (reduce dose ofclarithromycin in renal impairment); plasmaconcentration of azithromycin and erythromycinpossibly increased by ritonavir; increased risk ofventricular arrhythmias when clarithromycin orerythromycin given with .saquinavir—avoidconcomitant use; plasma concentration ofclarithromycin increased by .tipranavir (reducedose of clarithromycin in renal impairment), alsoclarithromycin increases plasma concentration oftipranavir; clarithromycin tablets reduce absorptionof zidovudine (give at least 2 hours apart). Anxiolytics and Hypnotics: clarithromycin anderythromycin inhibit metabolism of .midazolam(increased plasma concentration with increasedsedation); erythromycin increases plasma concentrationof buspirone (reduce dose of buspirone);erythromycin inhibits the metabolism of zopicloneAprepitant: clarithromycin possibly increases plasmaconcentration of aprepitant. Atomoxetine: increased risk of ventricular arrhythmiaswhen parenteral erythromycin given with.atomoxetine. Calcium-channel Blockers: erythromycin possiblyinhibits metabolism of felodipine (increased plasmaconcentration); avoidance of erythromycin advisedby manufacturer of lercanidipine; clarithromycin anderythromycin possibly inhibit metabolism of.verapamil (increased risk of toxicity)Cardiac Glycosides: macrolides increase plasma concentrationof digoxin (increased risk of toxicity). Ciclosporin: macrolides possibly inhibit metabolism of.ciclosporin (increased plasma concentration);clarithromycin and erythromycin inhibit metabolismof .ciclosporin (increased plasma concentration)Cilostazol: erythromycin increases plasma concentrationof cilostazol (consider reducing dose of cilostazol). Clopidogrel: erythromycin possibly reduces antiplateleteffect of .clopidogrel. Colchicine: azithromycin, clarithromycin and erythromycinpossibly increase risk of .colchicine toxicity—suspend or reduce dose of colchicine (avoid concomitantuse in hepatic or renal impairment)Corticosteroids: erythromycin possibly inhibitsmetabolism of corticosteroids; erythromycin inhibitsthe metabolism of methylprednisolone; clarithromycinpossibly increases plasma concentration ofmethylprednisolone. Cytotoxics: clarithromycin possibly increases plasmaconcentration of .everolimus—manufacturer ofeverolimus advises avoid concomitant use; erythromycinincreases plasma concentration of.everolimus; avoidance of clarithromycin advised bymanufacturer of .nilotinib and .pazopanib; in vitrostudies suggest a possible interaction betweenerythromycin and docetaxel (consult docetaxelproduct literature); increased risk of ventriculararrhythmias when erythromycin given with .arsenictrioxide; erythromycin increases toxicity of.vinblastine—avoid concomitant use; possibleincreased risk of neutropenia when clarithromycingiven with .vinorelbine. Diuretics: clarithromycin increases plasma concentrationof .eplerenone—avoid concomitant use;erythromycin increases plasma concentration ofeplerenone (reduce dose of eplerenone)Dopaminergics: macrolides possibly increase plasmaconcentration of bromocriptine andMacrolidesDopaminergics (continued)cabergoline (increased risk of toxicity); erythromycinincreases plasma concentration ofbromocriptine and cabergoline (increased risk oftoxicity). Ergot Alkaloids: increased risk of ergotism whenmacrolides given with .ergotamine and methysergide—avoidconcomitant use. 5HT 1 Agonists: clarithromycin and erythromycinincrease plasma concentration of .eletriptan (risk oftoxicity)—avoid concomitant use. Ivabradine: clarithromycin possibly increases plasmaconcentration of .ivabradine—avoid concomitantuse; increased risk of ventricular arrhythmias whenerythromycin given with .ivabradine—avoid concomitantuseLeukotriene Receptor Antagonists: erythromycinreduces plasma concentration of zafirlukast. Lipid-regulating Drugs: clarithromycin increasesplasma concentration of .atorvastatin and pravastatin;possible increased risk of myopathy whenerythromycin given with atorvastatin; erythromycinincreases plasma concentration of pravastatin;erythromycin reduces plasma concentration of rosuvastatin;increased risk of myopathy whenclarithromycin or erythromycin given with.simvastatin (avoid concomitant use)Oestrogens: erythromycin increases plasma concentrationof estradiolParasympathomimetics: erythromycin increasesplasma concentration of galantamine. Pentamidine Isetionate: increased risk of ventriculararrhythmias when parenteral erythromycin givenwith .pentamidine isetionateProgestogens: erythromycin increases plasma concentrationof dienogest. Ranolazine: clarithromycin possibly increases plasmaconcentration of .ranolazine—manufacturer ofranolazine advises avoid concomitant useSildenafil: clarithromycin possibly increases plasmaconcentration of sildenafil—reduce initial dose ofsildenafil; erythromycin increases plasma concentrationof sildenafil—reduce initial dose of sildenafil. Sirolimus: clarithromycin increases plasma concentrationof .sirolimus—avoid concomitant use; plasmaconcentration of both drugs increased whenerythromycin given with .sirolimus. Tacrolimus: clarithromycin and erythromycin increaseplasma concentration of .tacrolimusTadalafil: clarithromycin and erythromycin possiblyincrease plasma concentration of tadalafil. Theophylline: azithromycin possibly increases plasmaconcentration of theophylline; clarithromycin inhibitsmetabolism of .theophylline (increased plasma concentration);erythromycin increases plasma concentrationof .theophylline (also theophylline mayreduce absorption of oral erythromycin)Ulcer-healing Drugs: plasma concentration oferythromycin increased by cimetidine (increased riskof toxicity, including deafness); plasma concentrationof both drugs increased when clarithromycin givenwith omeprazoleVaccines: antibacterials inactivate oral typhoidvaccine—see p. 620Vardenafil: erythromycin increases plasma concentrationof vardenafil (reduce dose of vardenafil)Magnesium (parenteral). Calcium-channel Blockers: profound hypotensionreported with concomitant use of parenteralmagnesium and .nifedipine in pre-eclampsiaMuscle Relaxants: parenteral magnesium enhanceseffects of non-depolarising muscle relaxants andsuxamethoniumMagnesium Salts (oral) see AntacidsMannitolCiclosporin: possible increased risk of nephrotoxicitywhen mannitol given with ciclosporinAppendix 1: Interactions