BNF for Children 2011-2012

664 Appendix 1: Interactions BNFC 2011–2012Appendix 1: InteractionsAntidepressants, SSRI (continued)Metoclopramide: CNS toxicity reported when SSRIsgiven with metoclopramide. Muscle Relaxants: fluvoxamine increases plasmaconcentration of .tizanidine (increased risk of toxicity)—avoidconcomitant useParasympathomimetics: paroxetine increases plasmaconcentration of galantamineRanolazine: paroxetine increases plasma concentrationof ranolazineRoflumilast: fluvoxamine inhibits the metabolism ofroflumilastSympathomimetics: metabolism of SSRIs possiblyinhibited by methylphenidate. Theophylline: fluvoxamine increases plasma concentrationof .theophylline (concomitant use shouldusually be avoided, but where not possible halvetheophylline dose and monitor plasma-theophyllineconcentration)Ulcer-healing Drugs: plasma concentration of citalopram,escitalopram and sertraline increased bycimetidine; fluvoxamine possibly increases plasmaconcentration of lansoprazole; plasma concentrationof escitalopram increased by omeprazoleAntidepressants, SSRI (related) see Duloxetine andVenlafaxineAntidepressants, TricyclicAdrenergic Neurone Blockers: tricyclics antagonisehypotensive effect of adrenergic neurone blockers. Alcohol: increased sedative effect when tricyclics givenwith .alcoholAlpha 2 -adrenoceptor Stimulants: avoidance of tricyclicsadvised by manufacturer of apraclonidine andbrimonidineAnaesthetics, General: increased risk of arrhythmiasand hypotension when tricyclics given with generalanaesthetics. Analgesics: increased risk of CNS toxicity whentricyclics given with .tramadol; side-effects possiblyincreased when tricyclics given with nefopam;sedative effects possibly increased when tricyclicsgiven with opioid analgesics. Anti-arrhythmics: increased risk of ventricular arrhythmiaswhen tricyclics given with .amiodarone—avoid concomitant use; increased risk of ventriculararrhythmias when tricyclics given with.disopyramide or .flecainide; avoidance of tricyclicsadvised by manufacturer of .dronedarone (risk ofventricular arrhythmias); increased risk of arrhythmiaswhen tricyclics given with .propafenone. Antibacterials: increased risk of ventricular arrhythmiaswhen tricyclics given with .moxifloxacin—avoid concomitant use. Anticoagulants: tricyclics may enhance or reduceanticoagulant effect of .coumarins. Antidepressants: possible increased serotonergiceffects when amitriptyline or clomipramine givenwith duloxetine; increased risk of hypertension andCNS excitation when tricyclics given with .MAOIs,tricyclics should not be started until 2 weeks afterstopping MAOIs (3 weeks if starting clomipramine orimipramine), also MAOIs should not be started for atleast 1–2 weeks after stopping tricyclics (3 weeks inthe case of clomipramine or imipramine); afterstopping tricyclics do not start .moclobemide for atleast 1 week; plasma concentration of some tricyclicsincreased by .SSRIs; plasma concentration of amitriptylinereduced by St John’s wort. Antiepileptics: tricyclics antagonise anticonvulsanteffect of .antiepileptics (convulsive thresholdlowered); metabolism of tricyclics accelerated by.carbamazepine (reduced plasma concentration andreduced effect); metabolism of tricyclics possiblyaccelerated by .phenobarbital (reduced plasma concentration);plasma concentration of tricyclics possiblyreduced by .phenytoinAntifungals: plasma concentration of tricyclics possiblyincreased by terbinafineAntidepressants, Tricyclic (continued)Antihistamines: increased antimuscarinic and sedativeeffects when tricyclics given with antihistamines. Antimalarials: avoidance of antidepressants advised bymanufacturer of .artemether/lumefantrineAntimuscarinics: increased risk of antimuscarinic sideeffectswhen tricyclics given with antimuscarinics. Antipsychotics: plasma concentration of tricyclicsincreased by .antipsychotics—possibly increasedrisk of ventricular arrhythmias; avoidance of tricyclicsadvised by manufacturer of .droperidol (risk ofventricular arrhythmias); possible increased antimuscarinicside-effects when tricyclics given withclozapine; increased risk of antimuscarinic sideeffectswhen tricyclics given with phenothiazines;increased risk of ventricular arrhythmias whentricyclics given with .pimozide—avoid concomitantuse. Antivirals: plasma concentration of tricyclics possiblyincreased by .ritonavir; increased risk of ventriculararrhythmias when tricyclics given with .saquinavir—avoid concomitant useAnxiolytics and Hypnotics: increased sedative effectwhen tricyclics given with anxiolytics and hypnotics. Atomoxetine: increased risk of ventricular arrhythmiaswhen tricyclics given with .atomoxetine; possibleincreased risk of convulsions when antidepressantsgiven with atomoxetine. Beta-blockers: plasma concentration of imipramineincreased by labetalol and propranolol; increased riskof ventricular arrhythmias when tricyclics given with.sotalolBupropion: plasma concentration of tricyclics possiblyincreased by bupropion (possible increased risk ofconvulsions)Calcium-channel Blockers: plasma concentration ofimipramine increased by diltiazem and verapamil;plasma concentration of tricyclics possibly increasedby diltiazem and verapamilCannabis Extract: possible increased risk of hypertensionand tachycardia when tricyclics given withcannabis extract. Clonidine: tricyclics antagonise hypotensive effect of.clonidine, also increased risk of hypertension onclonidine withdrawal. Cytotoxics: increased risk of ventricular arrhythmiaswhen amitriptyline or clomipramine given with.arsenic trioxideDisulfiram: metabolism of tricyclics inhibited bydisulfiram (increased plasma concentration); concomitantamitriptyline reported to increase disulfiramreaction with alcoholDiuretics: increased risk of postural hypotension whentricyclics given with diuretics. Dopaminergics: caution with tricyclics advised bymanufacturer of entacapone; increased risk of CNStoxicity when tricyclics given with .rasagiline; CNStoxicity reported when tricyclics given with.selegilineHistamine: tricyclics theoretically antagonise effects ofhistamine—manufacturer of histamine advises avoidconcomitant useLithium: risk of toxicity when tricyclics given withlithiumMoxonidine: tricyclics possibly antagonise hypotensiveeffect of moxonidine (manufacturer of moxonidineadvises avoid concomitant use)Muscle Relaxants: tricyclics enhance muscle relaxanteffect of baclofenNicorandil: tricyclics possibly enhance hypotensiveeffect of nicorandilNitrates: tricyclics reduce effects of sublingual tabletsof nitrates (failure to dissolve under tongue owing todry mouth)Oestrogens: antidepressant effect of tricyclics antagonisedby oestrogens (but side-effects of tricyclicspossibly increased due to increased plasma concentration)