Phenytoin moderately reduces
digoxin levels, but the
clinical significance of this is unknown. There are also isolated case reports of marked bradycardia in patients taking
digoxin with
phenytoin. Fatalities have been reported when
phenytoin was used in cases of suspected
digoxin toxicity.
It would seem sensible to monitor the effects of concurrent use and consider monitoring
digoxin levels if an interaction is suspected. The use of
phenytoin in
digoxin toxicity appears to be obsolete.