Azithromycin

How it works

It inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit and preventing peptide chain elongation, conferring activity against many Gram-positive, atypical and some Gram-negative organisms.

Prescribing in practice

• Because azithromycin can prolong the QT interval, avoid or use with caution in those with known QT prolongation, significant cardiac disease, electrolyte imbalance or other QT-prolonging medicines.
• Rare but serious hepatotoxicity has been reported, and treatment should be stopped if signs of liver injury occur.
• It may interact with drugs such as certain ergot alkaloids and statins, so concomitant therapy should be reviewed.

Monitoring

Routine monitoring is not usually required for short courses, but assess liver function and cardiac risk where clinically indicated.

Counselling the patient

• Finish the full course as prescribed.
• Seek advice if you develop palpitations, fainting or jaundice.
• Let your clinician know about other medicines and any heart conditions.

Evidence & guidelines

Azithromycin is widely used across UK antimicrobial guidance, and the MHRA has issued reminders regarding its potential to prolong the QT interval.