What are the contraindications for Azithromycin (macrolide antibiotic)?

Azithromycin Contraindications

Azithromycin is contraindicated in patients with hypersensitivity to azithromycin, erythromycin, any macrolide, or any ketolide antibiotics, and in those with a history of cholestatic jaundice or hepatic dysfunction associated with previous use of azithromycin. 1

Primary Contraindications

• Hypersensitivity reactions:

  • Previous allergic reactions to azithromycin or any macrolide/ketolide antibiotic
  • History of Stevens-Johnson syndrome, toxic epidermal necrolysis, or other severe cutaneous adverse reactions with macrolides 2

• Hepatic conditions:

  • History of cholestatic jaundice/hepatic dysfunction with previous azithromycin use
  • Active liver disease requiring monitoring if azithromycin must be used 1, 2

• Cardiac conditions requiring caution or avoidance:

  • Known QT interval prolongation
  • History of torsades de pointes
  • Congenital long QT syndrome
  • Uncompensated heart failure
  • Bradyarrhythmias 2

Drug Interactions Requiring Avoidance

Azithromycin should not be used concurrently with:

• QT-prolonging medications:

  • Class IA antiarrhythmics (quinidine, procainamide)
  • Class III antiarrhythmics (dofetilide, amiodarone, sotalol)
  • Certain antiemetics (domperidone)
  • Antipsychotics with known QT effects 1, 2

• Medications with serious interaction potential:

  • Ergot derivatives (risk of ergotism)
  • Patients taking medications with narrow therapeutic windows that interact with azithromycin 1

Special Populations Requiring Caution

• Non-tuberculous mycobacterial (NTM) infections:

  • Current NTM infection is a contraindication to low-dose macrolide monotherapy
  • Patients should be screened for NTM before starting long-term azithromycin therapy 1

• Myasthenia gravis:

  • Use with extreme caution as azithromycin may exacerbate symptoms 1, 3

• Electrolyte abnormalities:

  • Uncorrected hypokalemia or hypomagnesemia increases risk of QT prolongation 2

• Elderly patients:

  • Higher susceptibility to QT interval prolongation effects 2

Monitoring Requirements When Use Is Necessary

If azithromycin must be used in patients with risk factors:

1. Cardiac monitoring:

   • Baseline ECG and follow-up monitoring in patients with cardiac risk factors
   • Discontinue immediately if QTc >500ms or if ventricular arrhythmias develop 1

2. Hepatic monitoring:

   • Baseline and periodic liver function tests
   • Discontinue immediately if signs of hepatitis occur 2

3. Electrolyte monitoring:

   • Check potassium and magnesium levels before initiating therapy in at-risk patients 2

Important Considerations for Clinical Practice

• The risk of QT prolongation and potentially fatal torsades de pointes should be carefully weighed against benefits, particularly in elderly patients and those with cardiac risk factors 2

• Patients on long-term azithromycin therapy should be monitored for development of resistant organisms, particularly in respiratory conditions 1

• When treating infections in patients with contraindications to azithromycin, alternative antibiotic classes should be considered based on the specific pathogen and infection site

• For patients with a history of macrolide allergy, cross-reactivity between different macrolides should be considered, with azithromycin potentially being more allergenic than clarithromycin in children 4

By carefully screening for these contraindications before prescribing azithromycin, clinicians can significantly reduce the risk of serious adverse events and improve patient safety.