In two cases the concurrent use of
intravenous calcium and
digoxin resulted in fatal arrhythmias. This seems to be the only direct
clinical evidence of a serious adverse interaction, although there is plenty of less direct evidence that an interaction is possible.
Intravenous calcium should be avoided in patients taking
digoxin. If that is not possible, it has been suggested that it should be given slowly or only in small amounts in order to avoid transient high
serum calcium levels.