How do macrolides and tetracyclines affect serum digoxin concentrations?
Macrolide antibiotics such as clarithromycin and erythromycin, and tetracyclines such as tetracycline and doxycycine alter the normal flora of the gut, including Eubacterium lentum. Under normal conditions, Eubacterium lentum inactivates digoxin in 10 – 15% of patients. This leads to increased digoxin bioavailability and a resultant increase in serum digoxin concentrations.
Lindenbaum J, et al. Inactivation of digoxin by the gut flora: reversal by antibiotic therapy. N Engl J Med. 1981;305:781-794; Rodin SM, Johnson BF. Pharmacokinetic interactions with digoxin.Clin Pharmacokinet. 1988;15:277-244
Contributed by: Kush Patel, MD