The patient was discharged on day 11 in good condition. Several reports of clarithromycin-induced drug interactions with digoxin and with warfarin have been published. Previously, case reports of macrolide-associated interactions mainly involved erythromycin, but more recently have implicated clarithromycin. The interaction between clarithromycin and warfarin is thought to occur from an inhibition of the cytochrome P450 drug metabolizing system. Clarithromycin is thought to cause digoxin toxicity by an alteration of the digoxin-metabolizing gut flora, thereby causing an increase in the digoxin concentration in susceptible individuals.
Drug interactions can occur by different mechanisms in the same patient.
Potential drug interactions can occur between commonly prescribed medications. It is important to monitor patients for symptoms and alterations in laboratory values to prevent not only serious complications, but also unnecessary hospitalizations.