Amoxicillin vs. Azithromycin
See how Amoxicillin and Azithromycin compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Amoxicillin is a penicillin-class antibiotic usually dosed two to three times a day for 7 to 10 days, while azithromycin is a macrolide often finished in just 3 to 5 days.
Azithromycin causes nausea and diarrhea more often than amoxicillin, but amoxicillin carries a higher risk of allergic rash and anaphylaxis in penicillin-sensitive patients.
Both cover many respiratory, skin, and ear infections, but azithromycin also treats chlamydia and other atypical bacteria that amoxicillin does not reach.
Amoxicillin vs. Azithromycin Drug Summary
Amoxicillin
Amoxicillin is an aminopenicillin antibiotic used to treat ear, sinus, throat, urinary, and skin infections caused by susceptible bacteria. It comes as a capsule, tablet, chewable, or liquid, usually taken two to three times a day for 7 to 10 days.
Azithromycin
Azithromycin is a macrolide antibiotic used for respiratory infections, skin infections, and sexually transmitted infections like chlamydia. It's usually taken as a tablet or liquid once daily for 3 to 5 days, or as a single dose for certain infections.
Amoxicillin vs. Azithromycin Side Effects
Amoxicillin
Azithromycin
Amoxicillin vs. Azithromycin Dosage
Amoxicillin
Azithromycin
| STAGE | DOSE | WHEN |
| Starting dose | 1 g three times daily | At the start |
| Maximum dose | 1 g three times daily | Same as starting |
| Dose changes | None | Fixed dose |
| STAGE | DOSE | WHEN |
| Starting dose | 500 mg once | Day 1 |
| Maximum dose | 5 mg/kg once daily | Days 2-5 |
| Dose changes | 4 increases | As tolerated |
Amoxicillin
| STAGE | DOSE | WHEN |
| Starting dose | 1 g three times daily | At the start |
| Maximum dose | 1 g three times daily | Same as starting |
| Dose changes | None | Fixed dose |
Azithromycin
| STAGE | DOSE | WHEN |
| Starting dose | 500 mg once | Day 1 |
| Maximum dose | 5 mg/kg once daily | Days 2-5 |
| Dose changes | 4 increases | As tolerated |
Amoxicillin vs. Azithromycin Indications
Amoxicillin
Amoxicillin treats a wide range of common bacterial infections, including ear, throat, sinus, urinary tract, and skin infections. It's also combined with other medications to eradicate H. pylori, the bacteria linked to stomach ulcers. It has no effect on viral illnesses like colds or the flu.
Ear, nose, and throat infections
Lower respiratory tract infections
Skin and skin structure infections
Urinary tract infections
H. pylori eradication (combination therapy)
Azithromycin
Azithromycin treats respiratory infections such as pneumonia, bronchitis, and sinusitis, along with skin infections and several sexually transmitted infections. It's also FDA-approved for pelvic inflammatory disease and ear infections in children. It is sometimes used off-label for traveler's diarrhea.
Community-acquired pneumonia
Acute bacterial sinusitis and bronchitis
Skin and skin structure infections
Chlamydia, urethritis, and cervicitis
Pelvic inflammatory disease
Amoxicillin vs. Azithromycin Pros and Cons
Amoxicillin
Amoxicillin has decades of established safety data and remains one of the most affordable, widely stocked antibiotics available. Its main drawback is a multiple-times-daily dosing schedule that some patients find harder to stick with over a full course.
Pros
Decades of established safety data
Roughly $11 to $25 per month, one of the least costly antibiotics
Lower risk of drug interactions than azithromycin
Considered safe as a first-line option in pregnancy
Cons
Requires dosing 2 to 3 times daily
Higher rash risk in penicillin-sensitive patients
Not effective against atypical bacteria like chlamydia
Cross-reactivity risk in patients with penicillin allergy
Azithromycin
Azithromycin's long tissue half-life allows short 3 to 5 day courses or even a single dose, which many patients find easier to complete. It carries a specific warning for QT prolongation and tends to cause more gastrointestinal side effects than amoxicillin.
Pros
Short 3 to 5 day or single-dose regimens
Once-daily dosing improves adherence
Covers atypical bacteria like chlamydia
Useful alternative for patients with penicillin allergy
Cons
Risk of QT prolongation and heart rhythm issues
Higher rates of nausea and diarrhea
Risk of serious liver toxicity
Brand Zithromax runs $150 to $400, well above generic amoxicillin
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