Two cases of clarithromycin-induced digoxin toxicity.

Two patients experienced clarithromycin-induced digoxin toxicity. Both had stable renal function within normal limits and had been maintained on a consistent dosage of digoxin. No changes in drug therapy had been made except for the addition of clarithromycin. Administration of clarithromycin to patients receiving long-term digoxin therapy may induce digoxin toxicity. When concomitant therapy is employed, patients should be closely monitored for clinical signs and symptoms of digoxin toxicity, and digoxin concentrations should be measured to avoid it.