Basic Information
ID DDInter1791 and DDInter488
Interaction Coadministration with deferasirox may significantly increase the plasma concentrations of theophylline. The proposed mechanism is deferasirox inhibition of CYP450 1A2, the isoenzyme primarily responsible for the metabolic clearance of theophylline.
Management Given the potential risk for theophylline toxicity, concomitant use with deferasirox should generally be avoided. Dosage adjustment for theophylline may be needed if coadministration with deferasirox is required. Close monitoring of serum theophylline levels is recommended, particularly following the addition, discontinuation, or change of dosage of deferasirox. Patients should be advised to notify their physician if they experience signs of theophylline toxicity such as nausea, vomiting, diarrhea, headache, restlessness, insomnia, seizures, palpitations, and cardiac arrhythmia.
References [1] "Product Information. Exjade (deferasirox)." Novartis Pharmaceuticals, East Hanover, NJ. [2] Sato J, Nakata H, Owada E, Kikuta T, Umetsu M, Ito K "Influence of usual intake of dietary caffeine on single-dose kinetics of theophylline in healthy human subjects." Eur J Clin Pharmacol 44 (1993): 295-8 [3] Jonkman JH, Sollie FA, Sauter R, Steinijans VW "The influence of caffeine on the steady-state pharmacokinetics of theophylline." Clin Pharmacol Ther 49 (1991): 248-55 [4] Wohlt PD, Zheng L, Gunderson S, Balzar SA, Johnson BD, Fish JT "Recommendations for the use of medications with continuous enteral nutrition." Am J Health Syst Pharm 66 (2009): 1438-67 [5] "Product Information. Exjade (deferasirox)." Novartis Pharmaceuticals, East Hanover, NJ.
Alternative for Theophylline R03D
Omalizumab Tezepelumab Mercaptopurine Benralizumab Reslizumab Dyphylline
Mepolizumab Zafirlukast Bromotheophylline
Alternative for Deferasirox V03A
Hydroxocobalamin Fomepizole Ipecac Nitrous acid Dexrazoxane Oxygen
Lanthanum carbonate Difelikefalin Cobicistat Deferoxamine Levoleucovorin
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Potential Metabolism Interactions
Substrate-Substrate Interaction：If more than one drug is metabolized by the same CYP, it is possible that its metabolism is inhibited because of the competition between the drugs. That means, it can be useful to lower the dosage of the drugs in the drug-cocktail because they remain longer in the organism than in monotherapy.
Inhibitor-Inhibitor Interaction：Combining two or more inhibitors of one CYP, should be compensated by lowering the dosage of these drugs because the metabolism is reduced and the drugs remain longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.
Inhibitor-Substrate Interaction：Combining drugs that have inhibitory effect and are substrates of one particular CYP, should be compensated by lowering the dosage. They rest longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.