Background: Various cardiac electrophysiologic effects
have been attributed to erythromycin. During the course of treating a
pneumonia patient with IV erythromycin, the conversion of atrial
fibrillation to a sinus rhythm, and its subsequent reversal, appeared
to be causally related to the introduction and cessation of this
Objective: This observation suggested the
need for studying the changes in the ECG following the use of IV
erythromycin in a typical clinical setting.
prospective comparative drug study.
university-affiliated teaching hospital.
Nineteen patients being treated for uncomplicated community-acquired
Intervention: IV erythromycin, 500 mg,
and/or IV cefuroxime, 750 mg, infused in 250 mL of saline over 20 min.
In the 11 patients who were receiving both of the antibiotics,
cefuroxime was administered immediately before erythromycin was
Measurements: The 12-lead ECG measurements
were obtained before infusion, at 5-min intervals during each infusion,
and at 5 and 10 min after the infusions had been completed. All of the
ECG complexes and intervals were measured using a software program
(Interpretive Cardiograph; Hewlett Packard; Palo Alto, CA).
Results: The administration of IV erythromycin increased
heart rate and prolonged the corrected QT (QTc) interval. These changes
were significant at 15 min of the infusion, and were no longer evident
5 min after the infusion had been stopped. The administration of IV
cefuroxime did not produce any ECG changes.
Conclusions: A single, standard dose of IV erythromycin
prolongs the QTc interval; therefore, the drug should always be
administered as a slow infusion. ECG monitoring should accompany
erythromycin therapy in critically ill patients, in patients with
electrolyte disorders, or in patients taking other drugs with similar
Abbreviations: QTc = corrected QT