Compare Amoxicillin vs. Keflex

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

Amoxil
(Amoxicillin)

Keflex
(Cephalexin)

Treats bacterial infections. Amoxil (Amoxicillin) is a good and cheap antibiotic to treat many types of bacterial infections. However, many bacteria are resistant to this medication.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
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5.0025641025641026Amoxicillin
Reviews for Amoxil (Amoxicillin)
62%
of people say Amoxil (Amoxicillin) is worth it
45%
say it works well
14%
say it's a big hassle
Reviews for Keflex (Cephalexin)
63%
+1% vs. Amoxil (Amoxicillin)
48%
+3% vs. Amoxil (Amoxicillin)
14%
Same vs. Amoxil (Amoxicillin)
Side effects
AmoxicillinKeflex

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

More about Amoxicillin 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
AmoxicillinKeflex
Amoxil (Amoxicillin) is an antibiotic. It kills bacteria and prevents them from reproducing and making their own protective covering.Keflex (Cephalexin) is an antibiotic. It kills bacteria by preventing them from making their own protective covering.
Type of medication
AmoxicillinKeflex
Antibiotic
Penicillin
Prescription only
Antibiotic
Cephalosporin
Prescription only
Available as
AmoxicillinKeflex
  • Pill
  • Chewable tablet
  • Liquid
  • Pill
  • Powder for oral suspension
Used for (click to learn more)
AmoxicillinKeflex
Risk factors for serious side effects
AmoxicillinKeflex
  • Long antibiotic treatment period
  • History of penicillin allergies
  • Using oral birth control pills
    Detailed Amoxil (Amoxicillin) risks & warnings »
      Detailed Keflex (Cephalexin) risks & warnings »
      Pregnancy category
      AmoxicillinKeflex
      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
      • Take with food to decrease upsetting your stomach (nausea, vomiting).
      • 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
      AmoxicillinKeflex
      • 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.
      Downsides and risks
      AmoxicillinKeflex
      • Suspension must be stored in the fridge.
      • Can make birth control pills and live vaccines less effective.
      • Many bacteria have developed resistance to this antibiotic.
      • Can cause diarrhea.
      • 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
      AmoxicillinKeflex
      • 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, making the medicine ineffective.
      • If you're taking birth control pills, this medication may make them less effective.
      • Take with food to decrease upsetting your stomach (nausea, vomiting).
      • If you're giving the suspension, you can mix it with a cold drink, but make sure to take it right away.
      • Keep the suspension form in the fridge. All other forms should be kept at room temperature.
      • You may have loose stool when taking this medicine, but it should get better soon after finishing the course. If the diarrhea worsens, tell your doctor.
      • 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 AmoxicillinSide effectsReviews & ratingsAlternativesFDA package insert
      More about KeflexSide effectsReviews & ratingsAlternativesFDA package insert