Most Azithromycin side effects are mild, dose-related and settle as treatment continues. The reactions that matter clinically are rare but need to be recognised quickly.
Key takeaways
- Common effects: GI upset, QT prolongation, transient LFT rise.
- Avoid Azithromycin in macrolide hypersensitivity and existing QT prolongation.
- Dose-related effects often resolve by stepping back one strength.
- Severe or persistent reactions warrant stopping and seeking review.
Frequency bands
| Frequency | Reactions | Action |
|---|---|---|
| Very common (>10%) | GI upset, QT prolongation | Usually self-limiting; supportive measures and reassurance. |
| Common (1–10%) | transient LFT rise | Review dose and timing; consider dose reduction. |
| Uncommon (<1%) | hypersensitivity, marked laboratory changes | Stop and arrange clinical assessment. |
| Rare | serious organ-specific reactions | Stop immediately; urgent medical attention. |
Reducing the burden
Take Azithromycin exactly as directed: 500 mg day 1 then 250 mg daily for 4 days, or 1 g single dose. Splitting titration into smaller steps, dosing with food where the label allows, and hydrating well cover most tolerability problems seen in practice.
Azithromycin at a glance
| Attribute | Detail |
|---|---|
| Drug class | macrolide antibiotic |
| Common brand | Zithromax |
| Licensed use | respiratory, skin and selected STI infections |
| Available strengths | 250 mg, 500 mg |
| Dosage form | film-coated tablet |
| Typical onset | clinical response in 48–72 hours |
| Duration / dosing interval | long tissue half-life, once-daily short course |
| Storage | below 30 °C |
