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.Kills bacteria. Keflex (Cephalexin) is good for treating many bacterial infections and is available as generic. However, if you are on medications to thin your blood, you can be more likely to bleed.
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Reviews & ratings
Button Group. All currently active
Button Group. All currently active
5.443093922651934Azithromycin
Reviews for Zithromax (Azithromycin)
74%
of people say Zithromax (Azithromycin) is worth it
59%
say it works well
11%
say it's a big hassle
Reviews for Keflex (Cephalexin)
63%
11% vs. Zithromax (Azithromycin)
48%
11% vs. Zithromax (Azithromycin)
14%
3% vs. Zithromax (Azithromycin)
Side effects
AzithromycinKeflex

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

More about 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
Antibiotic
Macrolide
Prescription only
Antibiotic
Cephalosporin
Prescription only
Available as
AzithromycinKeflex
  • Pill
  • Liquid
  • Eye drops
  • Pill
  • Powder for oral suspension
Used for (click to learn more)
AzithromycinKeflex
Risk factors for serious side effects
AzithromycinKeflex
      • History of liver disease
      • History of myasthenia gravis
      Detailed Zithromax (Azithromycin) risks & warnings »
        Detailed Keflex (Cephalexin) risks & warnings »
        Pregnancy category
        AzithromycinKeflex
        BFDA pregnancy category (Probably safe)

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

        See the FDA package insert
        BFDA pregnancy category (Probably safe)

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

        See the FDA package insert
        Alcohol
        No specific alcohol-related info.No specific alcohol-related info.
        Food
        • Can be taken with or without food.
        • Can take with or without food.
        • Can be taken with or without food.
        Kidneys and liver
        No specific kidneys and liver-related info.No specific kidneys and liver-related info.
        Sex
        No specific sex-related info.No specific sex-related info.
        Sleep
        No specific sleep-related info.No specific sleep-related info.
        Weight
        No specific weight-related info.No specific weight-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.
        • 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.
        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.
        • If you're on blood thinners (anticoagulants), talk to your doctor, it may make you more likely to bleed.
        • If you have to take any live vaccines, talk to your doctor. You may have to postpone it.
        • Can cause diarrhea.
        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.
        • Take this medication exactly as your doctor tells you to.
        • Store the suspension in the refrigerator. All other forms can be kept at room temperature.
        • Space out vitamins by a couple hours if you're taking this medication.
        Learn more
        More about AzithromycinSide effectsReviews & ratingsAlternativesFDA package insert
        More about KeflexSide effectsReviews & ratingsAlternativesFDA package insert