BNF for Children 2011-2012

BNFC 2011–2012 Appendix 1: Interactions 681Carbamazepine (continued). Lipid-regulating Drugs: carbamazepine reducesplasma concentration of .simvastatin—considerincreasing dose of simvastatinLithium: neurotoxicity may occur when carbamazepinegiven with lithium without increased plasma concentrationof lithiumMuscle Relaxants: carbamazepine antagonises musclerelaxant effect of non-depolarising muscle relaxants(accelerated recovery from neuromuscular blockade). Oestrogens: carbamazepine accelerates metabolism of.oestrogens (reduced contraceptive effect—seep. 398). Orlistat: possible increased risk of convulsions whenantiepileptics given with .orlistat. Progestogens: carbamazepine accelerates metabolismof .progestogens (reduced contraceptive effect—seep. 398)Retinoids: plasma concentration of carbamazepinepossibly reduced by isotretinoinTheophylline: carbamazepine accelerates metabolismof theophylline (reduced effect)Thyroid Hormones: carbamazepine acceleratesmetabolism of thyroid hormones (may increaserequirements for thyroid hormones in hypothyroidism)Tibolone: carbamazepine accelerates metabolism oftibolone (reduced plasma concentration). Ulcer-healing Drugs: metabolism of carbamazepineinhibited by .cimetidine (increased plasma concentration). Ulipristal: avoidance of carbamazepine advised bymanufacturer of .ulipristal (contraceptive effect ofulipristal possibly reduced)Vitamins: carbamazepine possibly increases requirementsfor vitamin DCarbapenems see Doripenem, Ertapenem, Imipenemwith Cilastatin, and MeropenemCarbonic Anhydrase Inhibitors see DiureticsCarboplatin see Platinum CompoundsCarboprost see ProstaglandinsCardiac GlycosidesACE Inhibitors: plasma concentration of digoxinpossibly increased by captoprilAlpha-blockers: plasma concentration of digoxinincreased by prazosinAminosalicylates: absorption of digoxin possiblyreduced by sulfasalazineAnalgesics: plasma concentration of cardiac glycosidespossibly increased by NSAIDs, also possible exacerbationof heart failure and reduction of renal functionAntacids: absorption of digoxin possibly reduced byantacids. Anti-arrhythmics: plasma concentration of digoxinincreased by .amiodarone, .dronedarone and.propafenone (halve dose of digoxin)Antibacterials: plasma concentration of digoxin possiblyincreased by gentamicin, telithromycin andtrimethoprim; absorption of digoxin reduced byneomycin; plasma concentration of digoxin possiblyreduced by rifampicin; plasma concentration ofdigoxin increased by macrolides (increased risk oftoxicity). Antidepressants: plasma concentration of digoxinreduced by .St John’s wort—avoid concomitant useAntidiabetics: plasma concentration of digoxin possiblyreduced by acarbose; plasma concentration ofdigoxin increased by sitagliptinAntiepileptics: plasma concentration of digoxin possiblyreduced by phenytoin. Antifungals: increased cardiac toxicity with cardiacglycosides if hypokalaemia occurs with.amphotericin; plasma concentration of digoxinincreased by .itraconazole. Antimalarials: plasma concentration of digoxin possiblyincreased by .chloroquine and hydroxychloroquine;possible increased risk of bradycardia whendigoxin given with mefloquine; plasma concentrationof digoxin increased by .quinineCardiac Glycosides (continued)Antimuscarinics: plasma concentration of digoxinpossibly increased by darifenacinAntivirals: plasma concentration of digoxin increasedby etravirine; plasma concentration of digoxinpossibly increased by ritonavirAnxiolytics and Hypnotics: plasma concentration ofdigoxin increased by alprazolam (increased risk oftoxicity)Beta-blockers: increased risk of AV block and bradycardiawhen cardiac glycosides given with betablockersCalcium Salts: arrhythmias can be precipitated whencardiac glycosides given with large intravenous dosesof calcium salts. Calcium-channel Blockers: plasma concentration ofdigoxin increased by .diltiazem, .lercanidipine and.nicardipine; plasma concentration of digoxin possiblyincreased by .nifedipine; plasma concentration ofdigoxin increased by .verapamil, also increased riskof AV block and bradycardia. Ciclosporin: plasma concentration of digoxin increasedby .ciclosporin (increased risk of toxicity). Colchicine: possible increased risk of myopathy whendigoxin given with .colchicineCorticosteroids: increased risk of hypokalaemia whencardiac glycosides given with corticosteroidsCytotoxics: absorption of digoxin tablets possiblyreduced by bleomycin, carmustine, cyclophosphamide,cytarabine, doxorubicin, melphalan, methotrexate,procarbazine and vincristine. Diuretics: increased cardiac toxicity with cardiacglycosides if hypokalaemia occurs with.acetazolamide, .loop diuretics or .thiazides andrelated diuretics; plasma concentration of digoxinpossibly increased by potassium canrenoate; plasmaconcentration of digoxin increased by.spironolactoneLenalidomide: plasma concentration of digoxin possiblyincreased by lenalidomideLipid-regulating Drugs: absorption of cardiac glycosidespossibly reduced by colestipol and colestyramine;plasma concentration of digoxin possiblyincreased by atorvastatinMuscle Relaxants: risk of ventricular arrhythmiaswhen cardiac glycosides given with suxamethonium;possible increased risk of bradycardia when cardiacglycosides given with tizanidinePenicillamine: plasma concentration of digoxin possiblyreduced by penicillamineRanolazine: plasma concentration of digoxin increasedby ranolazineSympathomimetics, Beta 2 : plasma concentration ofdigoxin possibly reduced by salbutamolTolvaptan: plasma concentration of digoxin increasedby tolvaptan (increased risk of toxicity)Ulcer-healing Drugs: plasma concentration of digoxinpossibly slightly increased by proton pump inhibitors;absorption of cardiac glycosides possibly reduced bysucralfateCarmustine. Antipsychotics: avoid concomitant use of cytotoxicswith .clozapine (increased risk of agranulocytosis)Cardiac Glycosides: carmustine possibly reducesabsorption of digoxin tabletsUlcer-healing Drugs: myelosuppressive effects ofcarmustine possibly enhanced by cimetidineCarteolol see Beta-blockersCarvedilol see Beta-blockersCaspofunginAntibacterials: plasma concentration of caspofungininitially increased and then reduced by rifampicin(consider increasing dose of caspofungin)Antiepileptics: plasma concentration of caspofunginpossibly reduced by carbamazepine and phenytoin—consider increasing dose of caspofunginAntivirals: plasma concentration of caspofungin possiblyreduced by efavirenz and nevirapine—considerincreasing dose of caspofunginAppendix 1: Interactions