Compare azithromycin vs. Keflex

Head-to-head comparisons of medication uses, side effects, ratings, and more.

Zithromax (azithromycin)

Prescription only

Keflex (cephalexin)

Prescription only
Treats bacterial infections.

Zithromax (azithromycin) is good for treating many bacterial infections and is available in generic form. However, it may cause headache, dizziness, or rash.

4.0/ 5 average rating with 909 reviewsforazithromycin
Treats bacterial infections.

Keflex (cephalexin) is good for treating many bacterial infections, and is available as a generic.

3.7/ 5 average rating with 686 reviewsforKeflex
Upsides
  • Available as a generic in the tablet and suspension form.
  • The suspension can be used if you have problems swallowing.
  • Used to treat many types of bacterial infections.
  • Bacteria is less resistant to this antibiotic, meaning that Zithromax (azithromycin) will fight off the bacteria better. Your doctor may run tests to see which antibiotics will kill the bacteria causing your infection.
  • Immediate release form can be taken with or without food.
  • Available in generic.
  • Available in different forms: tablet, capsule, and suspension.
  • Used to treat many types of bacterial infections.
  • Can be taken with or without food.
  • Generally few side effects compared with other antibiotics.
Downsides
  • Must space out antacids by at least 2 hours.
  • Use with caution if you have liver disease.
  • Must be used with caution if you are on medications to thin the blood (anticoagulants) because of increased risk of bleeding.
  • Can cause diarrhea.
  • You may need to take Keflex (cephalexin) 2 to 4 times a day, which can be hard to remember.
  • If you're allergic to penicillins or other antibiotics, you might not be able to take this medicine.
Used for
Dosage forms
  • Pill
  • Liquid
  • Extended-release liquid
  • Pill
  • Liquid
Price
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Reviews
909 reviews so far
74%
saidit'sworth it
59%
saiditworked well
11%
saidit'sa big hassle

Have you used Zithromax (azithromycin)?

Leave a review
686 reviews so far
64%
saidit'sworth it
48%
saiditworked well
14%
saidit'sa big hassle

Have you used Keflex (cephalexin)?

Leave a review
Side effects
3possible side effects
  • Vomiting
    5%
  • Diarrhea
    4%
  • Abdominal pain
    2%
See more detailed side effects
The Keflex (cephalexin) FDA package insert doesn’t have numbers about how common side effects are.
Risks and risk factors
  • Diarrhea caused by bacteria (Clostridium difficile)
  • Liver damage
    • History of liver disease
  • Myasthenia gravis
    • Myasthenia gravis
  • Serious allergic reaction
  • Abnormal heartbeat
    • QT prolongation
    • Arrhythmia
    • Drugs that cause prolonged QT interval
    • Abnormal electrolytes
    • Elderly
See more detailed risks and warnings
  • Diarrhea
  • New infections while taking Keflex (cephalexin)
    • Weakened immune system
    • Not taking Keflex (cephalexin) correctly
  • Allergic reaction
    • History of penicillin or cephalosporin allergies
See more detailed risks and warnings