Prescription onlyLower-cost generic available



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Kills bacteria.

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Prescription onlyLower-cost generic available

Our bottom line

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.


  • 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.
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  • 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.

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What to expect when you take Keflex (Cephalexin)

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Tips from our pharmacists
  • 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.
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Side effects for Keflex (Cephalexin)

Manufacturers don’t say how common these side effects are

  • Abdominal pain
  • Agitation
  • Anal itching
  • Confusion
  • Deep skin swelling
  • Destruction of red blood cells
  • Diarrhea
  • Dizziness
  • Eosinophilia
  • Erythema multiforme
  • Fatigue
  • Genital candidiasis
  • Hallucination
  • Headache
  • Hives
  • Indigestion
  • Itching
  • Joint disorder
  • Joint inflammation
  • Joint pain
  • Liver inflammation
  • Low white blood cells
  • Nephropathy
  • Rash
  • Stevens-johnson syndrome
  • Thrombocytopenia
  • Upset stomach
  • Vaginal discharge
  • Vaginal inflammation
  • Yellow skin or eyes

Risks and Warnings for Keflex (Cephalexin)

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  • As with all antibiotics, Keflex (Cephalexin) can cause diarrhea. If this happens while you're taking the medication, taking probiotics in the form of yogurt, supplements or drinks a few hours after you take the medication may help. If you develop an unusual diarrhea with loose or bloody stools weeks after you finish the medication, talk to your doctor as this can be a rare but serious side effect.

Means that some groups have a high risk of experiencing this side effect

Tips from pharmacists and people taking Keflex (Cephalexin)

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The FDA category for this medication is B. It is advised that you: Probably safe
  • Upsides and downsides from our pharmacists
  • Can be taken with or without food.