A possible interaction of potential clinical interest between digoxin and acarbose.

This case report describes a 69-year-old woman with diabetes mellitus and heart failure who repeatedly had unusual subtherapeutic levels of plasma digoxin. When the drug therapeutic regimen was checked it was found that a new drug, acarbose, had been added to the therapeutic regimen before the unexpected laboratory reported results. Because other drugs included in her therapeutic menu were rejected as being responsible for decreased levels of digoxin, it was recommended to discontinue acarbose to evaluate its role. In the absence of acarbose, the plasma concentration of digoxin increased to the therapeutic range. We concluded that acarbose may be responsible for a pharmacokinetic interaction with digoxin by a still unknown mechanism. Although discontinuation of acarbose was recommended, the attending physician discontinued administration of digoxin because the clinical condition of the patient did not get worse during subtherapeutic levels of digoxin.