Risk factors for toxicity
Several factors increase a patient’s risk of toxicity from chronic digoxin accumulation. These include:
- advanced age
- intercurrent acute illness and pre-existing medical conditions—kidney impairment, hypokalaemia, hypomagnesaemia, hypercalcaemia, myocardial ischaemia, hypoxia and acidosis
- drugs—beta blockers, calcium channel blockers, potassium-sparing diuretics, NSAIDs, macrolide antibiotics.
Digoxin is a substrate of the P-glycoprotein drug transporter. People taking drugs that inhibit P-glycoprotein are more susceptible to chronic digoxin toxicity because these drugs can raise serum digoxin concentration and prolong its half-life1.