Augmentin vs. Zithromax

See how Augmentin and Zithromax compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Augmentin is a penicillin-class antibiotic with a beta-lactamase inhibitor, while Zithromax is a macrolide, so they work differently against bacteria and cover different infections.

  • Augmentin typically requires multiple daily doses for 7 to 10 days, while Zithromax often uses a short 5-day pack or even a single dose.

  • Zithromax carries a risk of heart rhythm problems that Augmentin does not, while Augmentin carries a higher rate of diarrhea linked to its clavulanate component.

Augmentin vs. Zithromax Drug Summary

Augmentin

Augmentin combines amoxicillin with clavulanate, a beta-lactamase inhibitor, making it a penicillin-class antibiotic effective against bacteria that would otherwise resist amoxicillin alone. It treats infections like sinusitis, ear infections, urinary tract infections, and pneumonia. It comes as a tablet, chewable, or liquid suspension, usually taken every 8 to 12 hours for 7 to 10 days.

Zithromax

Zithromax, known generically as azithromycin, is a macrolide antibiotic that treats respiratory infections, skin infections, and certain sexually transmitted infections. It is taken as a tablet or liquid, often as a 5-day tapering dose pack known as the Z-Pak, or sometimes as a single dose. Its long tissue half-life lets it keep working after the last dose is taken.

Augmentin vs. Zithromax Side Effects

Augmentin

Most common
Nausea (3%)
Vomiting (1%)
Diarrhea/loose stools (9%)
Skin rash/urticaria (3%)

Zithromax

Most common
Nausea (3% to 18%)
Vomiting (2% to 7%)
Diarrhea (5% to 14%)
Abdominal pain (3% to 7%)

Augmentin vs. Zithromax Dosage

Augmentin

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 250 mg/125 mg q8h At the start
Maximum dose 2000 mg/125 mg q12h If needed
Dose changes 4 increases As tolerated

Zithromax

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 500 mg once daily Day 1
Maximum dose 30 mg/kg single dose If needed
Dose changes 5 increases As tolerated

Augmentin vs. Zithromax Indications

Augmentin

Augmentin is FDA-approved for common bacterial infections including sinus infections, ear infections, urinary tract infections, and pneumonia. It is not effective against viral infections like the common cold, and it should not be used in anyone with a history of penicillin allergy or prior liver problems linked to amoxicillin/clavulanate.

  • Lower respiratory tract infections

  • Acute bacterial otitis media

  • Acute bacterial sinusitis

  • Skin and skin structure infections

  • Urinary tract infections

Zithromax

Zithromax is FDA-approved for respiratory infections, skin infections, and sexually transmitted infections such as chlamydia and gonorrhea-related urethritis. It is also used off-label for traveler's diarrhea and chlamydial conjunctivitis, though these are not FDA-approved indications. Like Augmentin, it does not treat viral infections.

  • Community-acquired pneumonia

  • Acute bacterial sinusitis

  • Skin and skin structure infections

  • Urethritis/cervicitis (chlamydia, gonorrhea)

  • Pharyngitis/tonsillitis (alternative therapy)

Augmentin vs. Zithromax Pros and Cons

Augmentin

Augmentin's added clavulanate broadens coverage against bacteria that produce beta-lactamase, making it useful for infections resistant to amoxicillin alone. It has decades of clinical use and comes in several formulations for different ages. It requires more frequent dosing than Zithromax and carries a higher risk of diarrhea.

Pros

  • Clavulanate component overcomes bacterial resistance to amoxicillin alone

  • Available in chewable, liquid, and extended-release forms for all ages

  • No FDA boxed warning

  • Covers urinary tract infections, which Zithromax is not approved to treat

Cons

  • Requires dosing every 8 to 12 hours for a full 7 to 10 day course

  • Higher rate of diarrhea and GI upset from the clavulanate component

  • Contraindicated with any history of amoxicillin/clavulanate-related liver injury

  • Not effective against atypical bacteria like Chlamydia or Mycoplasma

Zithromax

Zithromax's long tissue half-life allows short courses, including single-dose treatment for some infections, which can improve completion rates. It covers atypical bacteria and certain sexually transmitted infections that Augmentin does not treat. It carries a cardiac risk that Augmentin does not share.

Pros

  • Short treatment courses, including single-dose options, improve adherence

  • Effective against atypical bacteria and certain sexually transmitted infections

  • Long-acting tissue levels continue working after the last dose

  • Approved for MAC disease prevention and treatment in immunocompromised patients

Cons

  • Carries a risk of QT prolongation and dangerous heart rhythm changes

  • Associated with increased cardiovascular death risk in certain regimens

  • Not first-line therapy for pharyngitis or tonsillitis

  • Rising bacterial resistance limits effectiveness of macrolides in some regions

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