BNF for Children 2011-2012

BNFC 2011–2012 Appendix 1: Interactions 675Atazanavir (continued). Calcium-channel Blockers: atazanavir increasesplasma concentration of .diltiazem (reduce dose ofdiltiazem); atazanavir possibly increases plasmaconcentration of verapamil. Ciclosporin: atazanavir possibly increases plasmaconcentration of .ciclosporin. Colchicine: atazanavir possibly increases risk of.colchicine toxicity—suspend or reduce dose ofcolchicine (avoid concomitant use in hepatic or renalimpairment). Cytotoxics: atazanavir possibly increases plasma concentrationof .everolimus—manufacturer of everolimusadvises avoid concomitant use; avoidance ofatazanavir advised by manufacturer of .pazopanib;atazanavir possibly inhibits metabolism of.irinotecan (increased risk of toxicity). Ergot Alkaloids: atazanavir possibly increases plasmaconcentration of .ergot alkaloids—avoid concomitantuse. Lipid-regulating Drugs: possible increased risk ofmyopathy when atazanavir given with atorvastatin;possible increased risk of myopathy when atazanavirgiven with .rosuvastatin—manufacturer of rosuvastatinadvises avoid concomitant use; increased risk ofmyopathy when atazanavir given with .simvastatin(avoid concomitant use)Oestrogens: atazanavir increases plasma concentrationof ethinylestradiolProgestogens: atazanavir increases plasma concentrationof norethisterone. Ranolazine: atazanavir possibly increases plasmaconcentration of .ranolazine—manufacturer ofranolazine advises avoid concomitant use. Sildenafil: atazanavir possibly increases side-effects of.sildenafil. Sirolimus: atazanavir possibly increases plasma concentrationof .sirolimus. Tacrolimus: atazanavir possibly increases plasma concentrationof .tacrolimus. Ulcer-healing Drugs: plasma concentration of atazanavirreduced by .histamine H 2 -antagonists; plasmaconcentration of atazanavir reduced by .protonpump inhibitors—avoid or adjust dose of both drugs(consult product literature)Atenolol see Beta-blockersAtomoxetine. Analgesics: increased risk of ventricular arrhythmiaswhen atomoxetine given with .methadone; possibleincreased risk of convulsions when atomoxetinegiven with tramadol. Anti-arrhythmics: increased risk of ventricular arrhythmiaswhen atomoxetine given with .amiodarone or.disopyramide. Antibacterials: increased risk of ventricular arrhythmiaswhen atomoxetine given with parenteral.erythromycin; increased risk of ventricular arrhythmiaswhen atomoxetine given with .moxifloxacin. Antidepressants: metabolism of atomoxetine possiblyinhibited by fluoxetine and paroxetine; possibleincreased risk of convulsions when atomoxetinegiven with antidepressants; atomoxetine should notbe started until 2 weeks after stopping .MAOIs, alsoMAOIs should not be started until at least 2 weeksafter stopping atomoxetine; increased risk of ventriculararrhythmias when atomoxetine given with.tricyclics. Antimalarials: increased risk of ventricular arrhythmiaswhen atomoxetine given with .mefloquine. Antipsychotics: increased risk of ventricular arrhythmiaswhen atomoxetine given with .antipsychoticsthat prolong the QT interval. Beta-blockers: increased risk of ventricular arrhythmiaswhen atomoxetine given with .sotalolBupropion: possible increased risk of convulsionswhen atomoxetine given with bupropion. Diuretics: risk of ventricular arrhythmias with atomoxetineincreased by hypokalaemia caused by.diureticsAtomoxetine (continued)Sympathomimetics, Beta 2 : Increased risk of cardiovascularside-effects when atomoxetine given withparenteral salbutamolAtorvastatin see StatinsAtovaquone. Antibacterials: plasma concentration of atovaquonereduced by .rifabutin and .rifampicin (possibletherapeutic failure of atovaquone); plasma concentrationof atovaquone reduced by tetracyclineAntivirals: atovaquone possibly reduces plasma concentrationof indinavir; atovaquone possibly inhibitsmetabolism of zidovudine (increased plasma concentration)Histamine: avoidance of atovaquone advised bymanufacturer of histamineMetoclopramide: plasma concentration of atovaquonereduced by metoclopramideAtracurium see Muscle RelaxantsAtropine see AntimuscarinicsAzathioprineACE Inhibitors: increased risk of anaemia or leucopeniawhen azathioprine given with captopril especially inrenal impairment; increased risk of anaemia whenazathioprine given with enalapril especially in renalimpairment. Allopurinol: enhanced effects and increased toxicity ofazathioprine when given with .allopurinol (reducedose of azathioprine to one quarter of usual dose)Aminosalicylates: possible increased risk of leucopeniawhen azathioprine given with aminosalicylates. Antibacterials: increased risk of haematological toxicitywhen azathioprine given with .sulfamethoxazole(as co-trimoxazole); increased risk of haematologicaltoxicity when azathioprine given with .trimethoprim(also with co-trimoxazole). Anticoagulants: azathioprine possibly reduces anticoagulanteffect of .coumarins. Antivirals: myelosuppressive effects of azathioprinepossibly enhanced by .ribavirin. Febuxostat: avoidance of azathioprine advised bymanufacturer of .febuxostatAzithromycin see MacrolidesAztreonam. Anticoagulants: aztreonam possibly enhances anticoagulanteffect of .coumarinsVaccines: antibacterials inactivate oral typhoidvaccine—see p. 620Baclofen see Muscle RelaxantsBalsalazide see AminosalicylatesBambuterol see Sympathomimetics, Beta 2Beclometasone see CorticosteroidsBemiparin see HeparinsBendamustine. Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis)Bendroflumethiazide see DiureticsBenperidol see AntipsychoticsBenzodiazepines see Anxiolytics and HypnoticsBenzthiazide see DiureticsBenzylpenicillin see PenicillinsBeta-blockersNote Since systemic absorption may follow topical applicationof beta-blockers to the eye the possibility of interactions,in particular, with drugs such as verapamil should beborne in mindACE Inhibitors: enhanced hypotensive effect whenbeta-blockers given with ACE inhibitorsAdrenergic Neurone Blockers: enhanced hypotensiveeffect when beta-blockers given with adrenergicneurone blockersAlcohol: enhanced hypotensive effect when betablockersgiven with alcoholAldesleukin: enhanced hypotensive effect when betablockersgiven with aldesleukin. Alpha-blockers: enhanced hypotensive effect whenbeta-blockers given with .alpha-blockers, alsoAppendix 1: Interactions