safety medical

Side Effects and Precautions of Keflex (Cephalexin)

Pharmacies, doctors’ offices, urgent cares, and hospitals all around the Western world are constantly presented with new medications that could help with various ailments. Unfortunately, all of these medications are chemically based and can produce a significant amount of side effects. Even as antibiotics like Keflex (cephalexin) perform their duties in fighting off harmful bacteria in the body, they may also cause uncomfortable side effects in the process.

Before delving into the side effects and precautions one should take before using Keflex, it is important to mention here that there is a such thing as healthy bacteria in the body, most of which reside in the gut to help with digestion and remove harmful toxins that we take in on a daily basis. Pharmaceutical antibiotics do not discriminate, however. They do not know the difference between good bacteria and bad bacteria, so these medications will usually kill them all off, which can cause some pretty significant GI conditions. Whenever you are prescribed an antibiotic, be sure to work in a healthy probiotic like yogurt with live active cultures or over-the-counter supplements to balance out the “cleaning” done by the antibiotic.

Side Effects of Cephalexin (Keflex)

Keflex (cephalexin) side effects can be mild to severe and dangerous. More serious side effects that would require you to immediately stop the antibiotic and seek medical attention include:

  • Severe allergic reaction like hives, rash, lip swelling, tongue swelling, fainting, and dizziness.
  • Severe nausea, vomiting, and/or diarrhea
  • Blood or mucus in the stools or vomit
  • Severe genital infection (yeasty)
  • Mouth sores that are painful
  • Difficulty breathing and wheezing
  • Difficulty swallowing

More minor side effects would include:

  • Minor nausea, which can be alleviated by taking the medication with food
  • Irregular bowel movements, which can be resolved with a probiotic and healthy nutrition
  • Mild skin rash or itching. General rule of thumb is if it’s tolerable, it’s minor.


There are certain precautions that should be taken before, during, and after taking Keflex.

  • As mentioned previously, work in a probiotic to avoid killing off the good bacteria and causing more symptoms. Your doctor may have some suggestions for this.
  • Keflex does not interact well with certain medications, so be sure to tell your doctor if you are taking any other antibiotic, as well as provide a list of any allergic reactions. It would be helpful to make a list of current medications and over-the-counter supplements you take daily or on an as-needed basis and keep that list on your person at all times.
  • Those who have a history of kidney or liver disease, colitis or other stomach disease should not take Keflex.
  • While Keflex is usually deemed safe for pregnant women, be sure to let your doctor know if you are/could be pregnant and if you’re breastfeeding.
  • Patients who have upcoming planned surgeries should avoid using Keflex.
2.5 / 52 votes (click to rate this article)


No comments yet

Leave a Reply

Submit comment