Dofetilide Theophylline

Studies in healthy subjects found that the concurrent use of theophylline 450 mg every 12 hours and dofetilide 500 micrograms every 12 hours did not alter the steady-state pharmacokinetics of either drug. - In addition, the increase in the QTc interval was no greater with the combination than with dofetilide alone. No special precautions appear to be necessary. 

Gardner MJ, Ashton HM, Willavize SA, Vincent J. The effects of concomitant dofetilide therapy on the pharmacokinetics and pharmacodynamics of theophylline. Clin Pharmacol Ther... 

There does not appear to be any interaction between theophylline and dofetilide. 

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