Reported Adverse Drug Reaction Cases
- Juurlink DN, Mamdani M, Kopp A, Laupacis A, Redelmeier DA. Drug-drug interactions among elderly patients hospitalized for drug toxicity. JAMA 2003;289:1652-58.
Clarithromycin + digoxin Interactions
A 75 year old female who had been taking digoxin 250 µg daily for almost four years was admitted with digoxin toxicity (4.2 nmol/L) on the third day after commencement of clarithromycin 250mg twice daily. The dose of digoxin was halved and clarithromycin stopped. She was discharged eight days later. Digoxin bioavailability is around 70% because p-glycoprotein in the gut wall pumps it back into the gut lumen, reducing absorption. Clarithromycin, and other macrolide antibiotics, inhibit the p-glycoprotein pump, increasing the amount of digoxin absorbed.