Doxycycline vs. Azithromycin

See how Doxycycline and Azithromycin compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Doxycycline treats a much broader range of infections, including malaria prevention and anthrax exposure, while azithromycin is mainly used for short-course bacterial infections like pneumonia and STIs.

  • Azithromycin's 3- to 5-day or single-dose regimens are usually easier to complete than doxycycline's typical 7- to 14-day course.

  • Doxycycline isn't recommended for young children or pregnant patients, while azithromycin carries its own risks of heart rhythm problems and liver damage.

Doxycycline vs. Azithromycin Drug Summary

Doxycycline

Doxycycline is a tetracycline-class antibacterial used to treat a wide range of bacterial infections, from respiratory and sexually transmitted infections to rickettsial diseases and malaria prevention. It's typically taken as an oral tablet or capsule once or twice daily, often for one to two weeks depending on the infection.

Azithromycin

Azithromycin is a macrolide antibacterial commonly prescribed for respiratory infections, skin infections, and certain sexually transmitted infections. It's usually taken as an oral tablet for just three to five days, or sometimes as a single dose, because it stays active in body tissue much longer.

Doxycycline vs. Azithromycin Side Effects

Doxycycline

Most common
Vomiting (common)
Nausea (common)
Diarrhea (common)
Photosensitivity (common)

Azithromycin

Most common
Vomiting (up to 7%)
Nausea (up to 18%)
Diarrhea (up to 14%)
Abdominal pain (up to 7%)

Doxycycline vs. Azithromycin Dosage

Doxycycline

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 200 mg total Day 1
Maximum dose 100 mg twice daily If needed
Dose changes 6 increases As tolerated

Azithromycin

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 500 mg once Day 1
Maximum dose 5 mg/kg once daily Days 2-5
Dose changes 6 increases As tolerated

Doxycycline vs. Azithromycin Indications

Doxycycline

Doxycycline is a tetracycline-class antibiotic approved for an unusually wide range of infections, from tick-borne rickettsial diseases to sexually transmitted infections and malaria prevention. It's also used off-label for Lyme disease and MRSA skin infections.

  • Rocky Mountain spotted fever and other rickettsial infections

  • Chlamydia and uncomplicated gonorrhea

  • Respiratory tract infections

  • Malaria prevention and anthrax post-exposure prophylaxis

  • Off-label: Lyme disease and MRSA skin infections

Azithromycin

Azithromycin is a macrolide antibiotic commonly prescribed for respiratory infections like pneumonia and sinusitis, as well as certain sexually transmitted infections. Its long-acting formula allows short 3- to 5-day courses or a single dose for some infections.

  • Community-acquired pneumonia and bronchitis flare-ups

  • Acute bacterial sinusitis and pharyngitis

  • Skin and skin structure infections

  • Urethritis, cervicitis, and pelvic inflammatory disease

  • Off-label: traveler's diarrhea

Doxycycline vs. Azithromycin Pros and Cons

Doxycycline

Doxycycline is a low-cost generic tetracycline with one of the broadest FDA-approved use lists of any oral antibiotic, covering everything from rickettsial disease to malaria prevention. It requires attention to sun exposure and hydration but carries no cardiac warnings.

Pros

  • Treats malaria prevention and anthrax exposure, uses azithromycin lacks

  • Effective for Lyme disease and other tick-borne infections

  • Low-cost generic widely available at most pharmacies

  • No QT-prolongation or cardiac arrhythmia warning on its label

Cons

  • Causes photosensitivity, requiring sun and UV precautions

  • Not approved for children under 8 or during pregnancy

  • Must be taken with plenty of water to avoid esophageal irritation

  • Typically requires a longer 7- to 14-day treatment course

Azithromycin

Azithromycin's short-course dosing makes it a convenient option for common infections like pneumonia and sinusitis, and it's generally considered safer for pregnant patients and young children. Its main trade-offs are a cardiac arrhythmia warning and increasing bacterial resistance.

Pros

  • Short 3- to 5-day or single-dose regimens improve adherence

  • Generally considered safer than doxycycline in young children and pregnancy

  • No photosensitivity or tooth-discoloration risk

  • Long tissue half-life keeps working after the course ends

Cons

  • Carries a warning for QT prolongation and cardiac arrhythmia

  • Risk of severe, sometimes fatal liver toxicity

  • Growing bacterial resistance limits use for some infections

  • Not effective against rickettsial or tick-borne infections

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