Management of Acute Azithromycin Overdose
Acute azithromycin overdose should be managed with supportive care and symptomatic treatment only, as there is no specific antidote and the drug has a favorable safety profile even in overdose situations.
Immediate Assessment and Monitoring
Obtain a 12-lead ECG immediately to assess for QTc prolongation, as azithromycin can cause QT interval prolongation and potentially life-threatening torsades de pointes, particularly in patients with pre-existing cardiac risk factors 1, 2.
Monitor vital signs closely, with particular attention to cardiac rhythm, as cardiovascular toxicity is the most serious potential complication of azithromycin overdose 1, 2.
Assess for gastrointestinal symptoms including nausea, vomiting, diarrhea, and abdominal pain, which are the most common manifestations of azithromycin toxicity 1, 2.
Gastrointestinal Decontamination
Activated charcoal may be considered if the patient presents within 1-2 hours of ingestion and can protect the airway, though the benefit must be weighed against the risk of aspiration 1.
Do not induce emesis, as this provides no proven benefit and increases the risk of aspiration 3, 4.
Gastric lavage is not recommended for azithromycin overdose, as the drug is rapidly absorbed and the procedure carries significant risks 4.
Supportive Care Measures
Provide intravenous fluid resuscitation if the patient develops significant vomiting or diarrhea leading to dehydration 3.
Correct electrolyte abnormalities, particularly hypokalemia and hypomagnesemia, as these can exacerbate QT prolongation and increase arrhythmia risk 1, 2.
Monitor liver function tests, as azithromycin can cause hepatotoxicity, though this is rare even in overdose 1.
Cardiac Management
If QTc exceeds 500 ms or increases >60 ms from baseline, discontinue any other QT-prolonging medications and consider cardiology consultation 2.
Continuous cardiac monitoring should be maintained for at least 24 hours in symptomatic patients or those with ECG abnormalities 1, 2.
For ventricular arrhythmias, standard Advanced Cardiac Life Support (ACLS) protocols should be followed, with magnesium sulfate as first-line therapy for torsades de pointes 3.
Observation Period and Disposition
Asymptomatic patients with normal ECGs who present more than 6 hours after ingestion can be observed at home with poison center follow-up, as significant toxicity is unlikely to develop after this timeframe 3, 4.
Symptomatic patients or those with ECG abnormalities should be admitted for continuous monitoring until symptoms resolve and the ECG normalizes 1, 2.
Patients with intentional overdose require psychiatric evaluation in addition to medical management 3, 4.
Key Clinical Pearls
Azithromycin has extensive tissue distribution and a prolonged elimination half-life of 68 hours, meaning that symptoms may persist for several days even with appropriate supportive care 2, 5, 6.
Serum azithromycin concentrations are not clinically useful in managing overdose, as tissue concentrations far exceed serum levels and do not correlate with toxicity 5, 6.
The risk of serious toxicity is relatively low compared to other antibiotics, as azithromycin has a wide therapeutic index 1, 5.
Patients taking other QT-prolonging medications (antiarrhythmics, antipsychotics, fluoroquinolones) are at significantly higher risk for cardiac complications and require more intensive monitoring 1, 2.
Elderly patients and those with pre-existing cardiovascular disease are at increased risk for cardiac toxicity and should be monitored more closely 2.