azithromycin vs erythromycin
PlainMeds reviewed this comparison against our methodology in August 2026. It places FDA and CMS record fields side by side, without recommending either medication.
Side-by-side comparison of azithromycin and erythromycin. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Zithromax, Z-Pack
E-Mycin, Ery-Tab
Azithromycin is an antibiotic that fights bacteria. It is used to treat many different types of infections.
Erythromycin Topical Solution is a medicine that you put on your skin to treat acne. It contains an antibiotic to help clear up your skin.
Azithromycin treats mild to moderate infections caused by certain bacteria. In adults, it can treat bronchitis, sinus infections, skin infections, urethritis, cervicitis, and genital ulcers. In children over 6 months old, it can treat ear infections and pneumonia. It can also treat pharyngitis/tonsillitis in children 2 years and older.
Erythromycin Topical Solution treats acne vulgaris. This medicine helps to reduce acne on your face, neck, shoulders, chest, and back. It works by fighting the bacteria that cause acne.
Azithromycin belongs to a class of drugs called macrolide antibiotics. It works by stopping the growth of bacteria. This helps your body fight off the infection.
Erythromycin is a macrolide antibiotic. It works by stopping the growth of bacteria. This helps to reduce inflammation and clear up acne.
- • Diarrhea (5-14%)
- • Nausea (3-18%)
- • Abdominal pain (3-7%)
- • Vomiting (2-7%)
- • Peeling
- • Dryness
- • Itching
- • Redness
- • Oily skin
- Dyspnoea 3,059
- Nausea 2,232
- Pain 2,205
- Pneumonia 2,085
- Cough 2,031
- Drug Hypersensitivity 4,088
- Nausea 1,271
- Vomiting 1,121
- Diarrhoea 1,069
- Dyspnoea 1,023
This drug can cause serious allergic reactions, liver problems, and heart rhythm changes. Tell your doctor right away if you have signs of an allergic reaction, like rash or swelling. Also, tell your doctor if you have liver problems, heart problems, or muscle weakness.
You should not use this medicine if you are allergic to any of its ingredients.
Studies haven't shown major risks to the baby during pregnancy. Talk to your doctor if you are pregnant or breastfeeding before taking this medicine.
It is not known if erythromycin topical solution can harm an unborn baby. Talk to your doctor if you are pregnant or breastfeeding.
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How to Read This azithromycin vs erythromycin Comparison
azithromycin is classified in the Macrolide Antibiotic drug class, while erythromycin sits within the Macrolide Antibiotic class. Because both drugs share the same classification, they are often considered interchangeable in theory, but clinical outcomes rarely track that cleanly. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, azithromycin has 11,612 submissions while erythromycin has 8,572. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for azithromycin or erythromycin.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.