Keflex

brand

Keflex Side Effects

Diarrhea, nausea, vomiting, or upset stomach may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Do not use anti-diarrhea or opioid medications if you have any of the following symptoms because these products may make them worse. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
  • Clostridioides difficile infection
  • vulvovaginal candidiasis
  • candidiasis
  • hemolytic anemia
  • aplastic anemia
  • hypoprothrombinemia
  • thrombocytopenic disorder
  • agranulocytosis
  • eosinophilia
  • acute confusion
  • agitation
  • hemorrhage
  • gastritis
  • dyspepsia
  • colitis
  • hepatitis
  • obstructive hyperbilirubinemia
  • interstitial nephritis
  • renal failure
  • kidney disease with reduction in glomerular filtration rate (GFR)
  • vaginitis
  • pemphigus
  • erythema multiforme
  • toxic epidermal necrolysis
  • Stevens-Johnson syndrome
  • pruritus ani
  • genital organ pruritus
  • pruritus of skin
  • urticaria
  • arthralgia
  • hallucinations
  • seizure disorder
  • dizziness
  • drug fever
  • fatigue
  • skin rash
  • hyperbilirubinemia
  • headache disorder
  • nausea
  • vomiting
  • diarrhea
  • abnormal hepatic function tests
  • anaphylaxis
  • angioedema
  • hypersensitivity drug reaction
  • serum sickness
  • paresthesia
  • acute abdominal pain
  • jaundice
  • acute generalized exanthematous pustulosis
  • DRESS syndrome
  • phlebitis after infusion

Drug Interactions

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

This medication may interfere with certain laboratory tests (including Coombs' test, certain urine glucose tests), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.