Compare Azithromycin vs. Keflex

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

Zithromax
(azithromycin)

Keflex
(cephalexin)

Kills bacteria. Zithromax (Azithromycin) is good for treating many bacterial infections. It is also available as generic. Talk to your doctor if you've ever had liver disease, myasthenia gravis, or on medications to thin the blood, as the doctor may write an alternative.Treats bacterial infections. Keflex (cephalexin) is good for treating many bacterial infections, and is available as a generic.
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Coupons for Azithromycin
Best available price for 1 (6 tablets of 250mg) z-pak of azithromycin
Coupons for Keflex
Best available price for 40 (500mg) capsules of cephalexin
Reviews & ratings
Filter group. All currently selected
Filter group. All currently selected
5.45Azithromycin
Reviews for Zithromax (azithromycin)
74%
of people (All ages) say Zithromax (azithromycin) is worth it
59%
say it works well
11%
say it's a big hassle
909 reviews
Have you used Zithromax (azithromycin)?
Worth itNot sureNot worth it
Reviews for Keflex (cephalexin)
64%
-10% worse vs. Zithromax (azithromycin)
48%
-11% worse vs. Zithromax (azithromycin)
14%
-3% worse vs. Zithromax (azithromycin)
686 reviews
Have you used Keflex (cephalexin)?
Worth itNot sureNot worth it
Side effects
AzithromycinKeflex
  • Diarrhea 5%
  • Nausea 3%
  • Abdominal pain 3%
  • Vomiting 6%
  • Rash 2%
  • Vaginitis 2%
More Azithromycin side effects »

The Keflex FDA package insert doesn’t have numbers about how common side effects are.

More about Keflex side effects »
How it works
AzithromycinKeflex
Zithromax (Azithromycin) is an antibiotic. It kills bacteria by preventing them from reproducing and repairing themselves.Keflex (cephalexin) is an antibiotic. It kills bacteria by preventing them from making their own protective covering.
Type of medication
AzithromycinKeflex
Prescription only
Prescription only
Available as
AzithromycinKeflex
  • Pill
  • Liquid
  • Eye drops
  • Pill
  • Liquid
Used for
AzithromycinKeflex
Risk factors for serious side effects
AzithromycinKeflex
  • History of liver disease
  • History of myasthenia gravis
Detailed Zithromax (azithromycin) risks & warnings »
  • Weakened immune system
  • Not taking Keflex (cephalexin) correctly
  • History of penicillin or cephalosporin allergies
Detailed Keflex (cephalexin) risks & warnings »
Pregnancy

Research studies with animals haven’t found a risk to unborn babies, but it hasn’t been properly studied in humans.

Research studies with animals haven’t found a risk to unborn babies, but it hasn’t been properly studied in humans.

Food
AzithromycinKeflex
  • Can be taken with or without food.
  • Can take with or without food.
  • Can be taken with or without food.
  • Can take with or without food.
Kidneys and liver
AzithromycinKeflex
  • There have been reports of liver damage that can require hospitalization or can cause death. These have been rare. Talk to your doctor if you notice pain in your abdomen, loss of appetite, yellowing of your skin or eyes, or dark colored urine.
No kidneys and liver related info.
Pain
AzithromycinKeflex
  • Can cause abdominal pain, diarrhea, vomiting, and nausea.
No pain related info.
Upsides and benefits
AzithromycinKeflex
  • Available in generic.
  • Available in different forms: tablet, capsule, and suspension.
  • Used to treat many types of bacterial infections.
  • Less resistance seen in bacteria to this antibiotic. Your doctor may run tests to see which antibiotics will kill the bacteria causing your infection.
  • 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 and risks
AzithromycinKeflex
  • Must space out antacids by at least 2 hours.
  • Has to be used with caution in people who've had liver disease.
  • Can't be used in people who've had myasthenia gravis.
  • Must be used with caution in people who are on medications to thin the blood (anticoagulants) because of increased risk of bleeding.
  • Can cause abdominal pain, diarrhea, vomiting, and nausea.
  • 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.
Tips from our pharmacists for people taking the medication
AzithromycinKeflex
  • Take the medication exactly how your doctor tells you to.
  • Can cause diarrhea, nausea or vomiting.
  • Space out any antacids with magnesium or aluminum by at least 2 hours.
  • Can take with or without food.
  • Finish all of the medicine your doctor gives you, even if you start to feel better. Stopping it early can cause the bacteria to develop resistance.
  • Store the suspension in the refrigerator. Shake well before using, and discard the bottle after 14 days.
  • Can take with or without food.
Learn more
More about AzithromycinSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Zithromax (azithromycin)?
Worth itNot sureNot worth it
More about KeflexSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Keflex (cephalexin)?
Worth itNot sureNot worth it