BNF for Children 2011-2012

BNFC 2011–2012 Appendix 1: Interactions 737Thyroid Hormones (continued)Lipid-regulating Drugs: absorption of levothyroxinereduced by colesevelam; absorption of thyroidhormones reduced by colestipol and colestyramineOestrogens: requirements for thyroid hormones inhypothyroidism may be increased by oestrogensOrlistat: possible increased risk of hypothyroidismwhen levothyroxine given with orlistatPolystyrene Sulphonate Resins: absorption oflevothyroxine reduced by polystyrene sulphonateresinsSevelamer: absorption of levothyroxine possiblyreduced by sevelamerUlcer-healing Drugs: absorption of levothyroxinereduced by cimetidine and sucralfateTiagabine. Antidepressants: anticonvulsant effect of antiepilepticspossibly antagonised by MAOIs and .tricyclic-relatedantidepressants (convulsive threshold lowered); anticonvulsanteffect of antiepileptics antagonised by.SSRIs and .tricyclics (convulsive thresholdlowered); avoid concomitant use of antiepilepticswith .St John’s wortAntiepileptics: plasma concentration of tiagabinereduced by carbamazepine, phenobarbital andphenytoin. Antimalarials: possible increased risk of convulsionswhen antiepileptics given with chloroquine andhydroxychloroquine; anticonvulsant effect of antiepilepticsantagonised by .mefloquine. Antipsychotics: anticonvulsant effect of antiepilepticsantagonised by .antipsychotics (convulsive thresholdlowered). Orlistat: possible increased risk of convulsions whenantiepileptics given with .orlistatTiaprofenic Acid see NSAIDsTiboloneAntibacterials: metabolism of tibolone accelerated byrifampicin (reduced plasma concentration)Antiepileptics: metabolism of tibolone accelerated bycarbamazepine (reduced plasma concentration);metabolism of tibolone accelerated by phenytoinTicarcillin see PenicillinsTigecyclineAnticoagulants: tigecycline possibly enhances anticoagulanteffect of coumarinsVaccines: antibacterials inactivate oral typhoidvaccine—see p. 620Tiludronic Acid see BisphosphonatesTimolol see Beta-blockersTinidazoleAlcohol: possibility of disulfiram-like reaction whentinidazole given with alcoholVaccines: antibacterials inactivate oral typhoidvaccine—see p. 620Tinzaparin see HeparinsTioguanine. Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis)Cytotoxics: increased risk of hepatotoxicity whentioguanine given with busulfanTiotropium see AntimuscarinicsTipranavirAnalgesics: plasma concentration of tipranavir possiblyreduced by buprenorphineAntacids: absorption of tipranavir reduced by antacids. Antibacterials: tipranavir increases plasma concentrationof .clarithromycin (reduce dose of clarithromycinin renal impairment), also plasmaconcentration of tipranavir increased by clarithromycin;tipranavir increases plasma concentration of.rifabutin (reduce dose of rifabutin); plasma concentrationof tipranavir possibly reduced by.rifampicin—avoid concomitant use; avoidance ofconcomitant tipranavir in severe renal and hepaticimpairment advised by manufacturer of.telithromycinTipranavir (continued)Anticoagulants: avoidance of tipranavir advised bymanufacturer of rivaroxaban. Antidepressants: plasma concentration of tipranavirpossibly reduced by .St John’s wort—avoid concomitantuseAntiepileptics: plasma concentration of tipranavirpossibly reduced by carbamazepineAntifungals: plasma concentration of tipranavirincreased by fluconazole. Antimalarials: caution with tipranavir advised bymanufacturer of artemether/lumefantrine; tipranavirpossibly increases plasma concentration of .quinine(increased risk of toxicity)Antimuscarinics: avoidance of tipranavir advised bymanufacturer of darifenacin. Antivirals: tipranavir reduces plasma concentration of.abacavir, .didanosine, .fosamprenavir, .lopinavir,.saquinavir and .zidovudine; plasma concentrationof tipranavir increased by atazanavir (also plasmaconcentration of atazanavir reduced); tipranavirreduces plasma concentration of .etravirine, alsoplasma concentration of tipranavir increased (avoidconcomitant use). Beta-blockers: manufacturer of tipranavir advisesavoid concomitant use with .metoprolol for heartfailure. Lipid-regulating Drugs: tipranavir possibly increasesplasma concentration of .atorvastatin (considerreducing dose of atorvastatin); tipranavir possiblyincreases plasma concentration of .rosuvastatin—manufacturer of rosuvastatin advises avoid concomitantuse; tipranavir possibly increases plasmaconcentration of .simvastatin—avoid concomitantuse. Ranolazine: tipranavir possibly increases plasma concentrationof .ranolazine—manufacturer of ranolazineadvises avoid concomitant use. Ulcer-healing Drugs: tipranavir reduces plasma concentrationof .esomeprazole and .omeprazoleVitamins: increased risk of bleeding when tipranavirgiven with high doses of vitamin ETirofibanIloprost: increased risk of bleeding when tirofibangiven with iloprostTizanidine see Muscle RelaxantsTobramycin see AminoglycosidesTocilizumab. Vaccines: avoid concomitant use of tocilizumab withlive .vaccines (see p. 599)Tolazoline see Alpha-blockersTolbutamide see AntidiabeticsTolcaponeAntidepressants: avoid concomitant use of tolcaponewith MAOIsMemantine: effects of dopaminergics possiblyenhanced by memantineMethyldopa: antiparkinsonian effect of dopaminergicsantagonised by methyldopaTolfenamic Acid see NSAIDsTolterodine see AntimuscarinicsTolvaptanAntibacterials: plasma concentration of tolvaptanreduced by rifampicinAntifungals: plasma concentration of tolvaptanincreased by ketoconazoleCardiac Glycosides: tolvaptan increases plasma concentrationof digoxin (increased risk of toxicity). Grapefruit Juice: plasma concentration of tolvaptanincreased by .grapefruit juice—avoid concomitantuseTopiramate. Antidepressants: anticonvulsant effect of antiepilepticspossibly antagonised by MAOIs and .tricyclic-relatedantidepressants (convulsive threshold lowered); anticonvulsanteffect of antiepileptics antagonised by.SSRIs and .tricyclics (convulsive thresholdAppendix 1: Interactions