Carbimazole slightly lowers
digoxin levels in euthyroid subjects. However, the drug- disease interaction that also occurs is probably of more importance. Hyperthyroid subjects are relatively resistant to the effects of
digoxin and so need higher doses. As treatment with
carbimazole progresses and they become euthyroid, the dosage of
digoxin will need to be decreased.
Monitor the outcome of resolving hyperthyroidism, checking for
digoxin overdosage, by
symptoms of bradycardia etc. Monitor
digoxin levels as necessary.