BNF for Children 2011-2012

714 Appendix 1: Interactions BNFC 2011–2012Appendix 1: InteractionsNSAIDs. Antivirals (continued)haematological toxicity when NSAIDs given withzidovudineBeta-blockers: NSAIDs antagonise hypotensive effectof beta-blockersBisphosphonates: indometacin increases bioavailabilityof tiludronic acidCalcium-channel Blockers: NSAIDs antagonise hypotensiveeffect of calcium-channel blockersCardiac Glycosides: NSAIDs possibly increase plasmaconcentration of cardiac glycosides, also possibleexacerbation of heart failure and reduction of renalfunction. Ciclosporin: increased risk of nephrotoxicity whenNSAIDs given with .ciclosporin; plasma concentrationof diclofenac increased by .ciclosporin (halvedose of diclofenac)Clonidine: NSAIDs antagonise hypotensive effect ofclonidineClopidogrel: increased risk of bleeding when NSAIDsgiven with clopidogrelCorticosteroids: increased risk of gastro-intestinalbleeding and ulceration when NSAIDs given withcorticosteroids. Cytotoxics: NSAIDs probably reduce excretion of.methotrexate (increased risk of toxicity); diclofenac,ibuprofen, indometacin, ketoprofen, meloxicam andnaproxen reduce excretion of .methotrexate(increased risk of toxicity); increased risk of bleedingwhen NSAIDs given with .erlotinibDesmopressin: indometacin enhances effects ofdesmopressinDiazoxide: NSAIDs antagonise hypotensive effect ofdiazoxide. Dimethyl sulfoxide: avoid concomitant use of sulindacwith .dimethyl sulfoxide. Diuretics: risk of nephrotoxicity of NSAIDs increasedby diuretics, also antagonism of diuretic effect;indometacin and ketorolac antagonise effects ofdiuretics; NSAIDs possibly antagonise diuretic effectof potassium canrenoate; occasional reports ofreduced renal function when indometacin given with.triamterene—avoid concomitant use; possibleincreased risk of hyperkalaemia when NSAIDs givenwith potassium-sparing diuretics and aldosteroneantagonists; increased risk of hyperkalaemia whenindometacin given with potassium-sparing diureticsand aldosterone antagonistsIloprost: increased risk of bleeding when NSAIDs givenwith iloprostLipid-regulating Drugs: excretion of meloxicamincreased by colestyramine. Lithium: NSAIDs reduce excretion of .lithium(increased risk of toxicity); ketorolac reduces excretionof .lithium (increased risk of toxicity)—avoidconcomitant useMethyldopa: NSAIDs antagonise hypotensive effect ofmethyldopaMifamurtide: avoidance of high doses of NSAIDsadvised by manufacturer of mifamurtideMoxonidine: NSAIDs antagonise hypotensive effect ofmoxonidineMuscle Relaxants: ibuprofen reduces excretion ofbaclofen (increased risk of toxicity); NSAIDs possiblyreduce excretion of baclofen (increased risk oftoxicity)Nitrates: NSAIDs antagonise hypotensive effect ofnitratesOestrogens: etoricoxib increases plasma concentrationof ethinylestradiolPenicillamine: possible increased risk of nephrotoxicitywhen NSAIDs given with penicillamine. Pentoxifylline: possible increased risk of bleeding whenNSAIDs given with pentoxifylline; increased risk ofbleeding when ketorolac given with .pentoxifylline(avoid concomitant use)Prasugrel: possible increased risk of bleeding whenNSAIDs given with prasugrelNSAIDs (continued). Probenecid: excretion of dexketoprofen, indometacin,ketoprofen and naproxen reduced by .probenecid(increased plasma concentration); excretion of ketorolacreduced by .probenecid (increased plasmaconcentration)—avoid concomitant use. Tacrolimus: possible increased risk of nephrotoxicitywhen NSAIDs given with tacrolimus; increased risk ofnephrotoxicity when ibuprofen given with.tacrolimusVasodilator Antihypertensives: NSAIDs antagonisehypotensive effect of hydralazine, minoxidil andsodium nitroprussideOctreotideAntidiabetics: octreotide possibly reduces requirementsfor insulin, metformin, repaglinide and sulfonylureas. Ciclosporin: octreotide reduces plasma concentrationof .ciclosporinDopaminergics: octreotide increases plasma concentrationof bromocriptineUlcer-healing Drugs: octreotide possibly delaysabsorption of cimetidineOestrogensNote Interactions of combined oral contraceptives may alsoapply to combined contraceptive patches and vaginal rings,see p. 398ACE Inhibitors: oestrogens antagonise hypotensiveeffect of ACE inhibitorsAdrenergic Neurone Blockers: oestrogens antagonisehypotensive effect of adrenergic neurone blockersAlpha-blockers: oestrogens antagonise hypotensiveeffect of alpha-blockersAnalgesics: plasma concentration of ethinylestradiolincreased by etoricoxibAngiotensin-II Receptor Antagonists: oestrogensantagonise hypotensive effect of angiotensin-IIreceptor antagonists. Antibacterials: plasma concentration of estradiolincreased by erythromycin; metabolism of oestrogensaccelerated by .rifamycins (reduced contraceptiveeffect—see p. 398). Anticoagulants: oestrogens may enhance or reduceanticoagulant effect of coumarins; oestrogens antagoniseanticoagulant effect of .phenindione. Antidepressants: contraceptive effect of oestrogensreduced by .St John’s wort (avoid concomitant use);oestrogens antagonise antidepressant effect of tricyclics(but side-effects of tricyclics possiblyincreased due to increased plasma concentration)Antidiabetics: oestrogens antagonise hypoglycaemiceffect of antidiabetics. Antiepileptics: metabolism of oestrogens acceleratedby .carbamazepine, .eslicarbazepine,.oxcarbazepine, .phenobarbital, .phenytoin,.rufinamide and .topiramate (reduced contraceptiveeffect—see p. 398); oestrogens reduce plasma concentrationof .lamotrigine—consider increasing doseof lamotrigine; ethinylestradiol possibly reducesplasma concentration of valproateAntifungals: oestrogens increase plasma concentrationof voriconazole; anecdotal reports of contraceptivefailure and menstrual irregularities when oestrogensgiven with griseofulvin; anecdotal reports of contraceptivefailure when oestrogens given with imidazoles;occasional reports of breakthrough bleedingwhen oestrogens (used for contraception) given withterbinafine. Antivirals: plasma concentration of ethinylestradiolincreased by atazanavir; metabolism of oestrogensaccelerated by .nelfinavir, .nevirapine and .ritonavir(reduced contraceptive effect—see p. 398)Anxiolytics and Hypnotics: oestrogens increaseplasma concentration of melatonin. Aprepitant: possible contraceptive failure of hormonalcontraceptives containing oestrogens when givenwith .aprepitant (alternative contraception recommended)