CARBIMAZOLE AND DIGOXIN

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.