In acute myocardial infarction, ischaemic heart disease or myocarditis, digoxin increases risk of arrhythmias.
Use digoxin cautiously in sick sinus syndrome (risk of severe bradycardia or sinoatrial block).
Digoxin may worsen cardiac function in severe aortic stenosis because it increases the force of myocardial contraction.
Digoxin increases risk of arrhythmias after DC cardioversion; withhold digoxin for 1–2 days before cardioversion or use lowest effective energy.
Hyperthyroidism—may decrease digoxin concentration and increase sympathetic tone; monitor digoxin concentration and alter dose when required or combine with another agent; dosage adjustment may be required when condition is corrected.
Hypothyroidism—may increase digoxin concentration; monitor digoxin concentration and alter dose as required; dosage adjustment may be required when condition is corrected.
Hypokalaemia, hypomagnesaemia, hypercalcaemia, acidosis, hypoxia—may increase sensitivity to digoxin (especially hypokalaemia); symptoms of toxicity may occur at lower digoxin concentrations.
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