BNF for Children 2011-2012

676 Appendix 1: Interactions BNFC 2011–2012Appendix 1: InteractionsBeta-blockers. Alpha-blockers (continued)increased risk of first-dose hypotension with postsynapticalpha-blockers such as prazosinAnaesthetics, General: enhanced hypotensive effectwhen beta-blockers given with general anaesthetics. Anaesthetics, Local: propranolol increases risk of.bupivacaine toxicityAnalgesics: hypotensive effect of beta-blockers antagonisedby NSAIDs; plasma concentration of esmololpossibly increased by morphineAngiotensin-II Receptor Antagonists: enhancedhypotensive effect when beta-blockers given withangiotensin-II receptor antagonists. Anti-arrhythmics: increased myocardial depressionwhen beta-blockers given with .anti-arrhythmics;increased risk of ventricular arrhythmias when sotalolgiven with .amiodarone, .disopyramide or.dronedarone—avoid concomitant use; increasedrisk of bradycardia, AV block and myocardialdepression when beta-blockers given with.amiodarone; plasma concentration ofmetoprolol and propranolol possibly increased bydronedarone; increased risk of myocardial depressionand bradycardia when beta-blockers given with.flecainide; propranolol increases risk of .lidocainetoxicity; plasma concentration of metoprolol andpropranolol increased by propafenone. Antibacterials: increased risk of ventricular arrhythmiaswhen sotalol given with .moxifloxacin—avoidconcomitant use; metabolism of bisoprolol andpropranolol accelerated by rifampicin (plasma concentrationsignificantly reduced); plasma concentrationof carvedilol, celiprolol and metoprolol reducedby rifampicin. Antidepressants: plasma concentration of metoprololincreased by citalopram and escitalopram; plasmaconcentration of propranolol increased by fluvoxamine;plasma concentration of metoprolol possiblyincreased by paroxetine (enhanced effect);labetalol and propranolol increase plasma concentrationof imipramine; enhanced hypotensive effectwhen beta-blockers given with MAOIs; increased riskof ventricular arrhythmias when sotalol given with.tricyclicsAntidiabetics: beta-blockers may mask warning signsof hypoglycaemia (such as tremor) with antidiabetics;beta-blockers enhance hypoglycaemic effect ofinsulinAntiepileptics: plasma concentration of propranololpossibly reduced by phenobarbital. Antihistamines: increased risk of ventricular arrhythmiaswhen sotalol given with .mizolastine—avoidconcomitant use. Antimalarials: avoidance of metoprolol and sotaloladvised by manufacturer of .artemether/lumefantrine;increased risk of bradycardia when betablockersgiven with mefloquine. Antimuscarinics: increased risk of ventricular arrhythmiaswhen sotalol given with .tolterodine. Antipsychotics: increased risk of ventricular arrhythmiaswhen sotalol given with .droperidol or.zuclopenthixol—avoid concomitant use; possibleincreased risk of ventricular arrhythmias when sotalolgiven with .haloperidol—avoid concomitant use;plasma concentration of both drugs may increasewhen propranolol given with .chlorpromazine;increased risk of ventricular arrhythmias when sotalolgiven with .amisulpride, .phenothiazines,.pimozide or .sulpiride; enhanced hypotensive effectwhen beta-blockers given with phenothiazines. Antivirals: increased risk of ventricular arrhythmiaswhen sotalol given with .saquinavir—avoid concomitantuse; avoidance of metoprolol for heart failureadvised by manufacturer of .tipranavirAnxiolytics and Hypnotics: enhanced hypotensiveeffect when beta-blockers given with anxiolytics andhypnoticsBeta-blockers (continued). Atomoxetine: increased risk of ventricular arrhythmiaswhen sotalol given with .atomoxetine. Calcium-channel Blockers: enhanced hypotensiveeffect when beta-blockers given with calciumchannelblockers; possible severe hypotension andheart failure when beta-blockers given with.nifedipine; increased risk of AV block and bradycardiawhen beta-blockers given with .diltiazem;asystole, severe hypotension and heart failure whenbeta-blockers given with .verapamil (see p. 109)Cardiac Glycosides: increased risk of AV block andbradycardia when beta-blockers given with cardiacglycosides. Ciclosporin: carvedilol increases plasma concentrationof .ciclosporin. Clonidine: increased risk of withdrawal hypertensionwhen beta-blockers given with .clonidine (withdrawbeta-blockers several days before slowly withdrawingclonidine)Corticosteroids: hypotensive effect of beta-blockersantagonised by corticosteroids. Cytotoxics: increased risk of ventricular arrhythmiaswhen sotalol given with .arsenic trioxideDiazoxide: enhanced hypotensive effect when betablockersgiven with diazoxide. Diuretics: enhanced hypotensive effect when betablockersgiven with diuretics; risk of ventriculararrhythmias with sotalol increased by hypokalaemiacaused by .loop diuretics or .thiazides and relateddiureticsDopaminergics: enhanced hypotensive effect whenbeta-blockers given with levodopaErgot Alkaloids: increased peripheral vasoconstrictionwhen beta-blockers given with ergotamine andmethysergide5HT 1 Agonists: propranolol increases plasma concentrationof rizatriptan (manufacturer of rizatriptanadvises halve dose and avoid within 2 hours ofpropranolol). Ivabradine: increased risk of ventricular arrhythmiaswhen sotalol given with .ivabradineMethyldopa: enhanced hypotensive effect when betablockersgiven with methyldopa. Moxisylyte: possible severe postural hypotension whenbeta-blockers given with .moxisylyteMoxonidine: enhanced hypotensive effect when betablockersgiven with moxonidineMuscle Relaxants: propranolol enhances effects ofmuscle relaxants; enhanced hypotensive effect whenbeta-blockers given with baclofen; possible enhancedhypotensive effect and bradycardia when betablockersgiven with tizanidineNitrates: enhanced hypotensive effect when betablockersgiven with nitratesOestrogens: hypotensive effect of beta-blockersantagonised by oestrogensParasympathomimetics: propranolol antagoniseseffects of neostigmine and pyridostigmine; increasedrisk of arrhythmias when beta-blockers given withpilocarpineProstaglandins: enhanced hypotensive effect whenbeta-blockers given with alprostadil. Ranolazine: avoidance of sotalol advised by manufacturerof .ranolazine. Sympathomimetics: increased risk of severe hypertensionand bradycardia when non-cardioselectivebeta-blockers given with .adrenaline (epinephrine),also reponse to adrenaline (epinephrine) may bereduced; increased risk of severe hypertension andbradycardia when non-cardioselective beta-blockersgiven with .dobutamine; possible increased risk ofsevere hypertension and bradycardia when noncardioselectivebeta-blockers given with .noradrenaline(norepinephrine)Thyroid Hormones: metabolism of propranolol acceleratedby levothyroxine