Cephalexin (Keflex)

Updated: Jun 20, 2021

Typically is supplied as the following:

  • Typically supplied as the following;

  • Oral Tablet: 250 MG, 500 MG

  • Oral Capsule: 250 MG, 500 MG, 750 MG

  • Oral Powder (Suspension): 125 MG/5 ML, 250 MG/5 ML

Cephalexin is a cephalosporin antibiotic that belongs to a class of medicines commonly referred to as Beta-lactams. This name, which is derived from its characteristic chemical structure, is generally used to refer to other antibiotics in this class, including penicillin, amoxicillin and other cephalosporin such as cefepime (omnicef). They are known to work by disrupting the growth of susceptible bug or bacteria. Cephalexin is often prescribed by physician to treat a whole host of infections including ear, nose and throat infections, lower respiratory infections, skin and soft tissue infections, among others. It is typically dosed 2 to 3 times daily for most infections and generally recommended to take with or following a meal.



I do not like taking antibiotics. If I start to feel better before completing the course of the treatment, can I stop it?

It may be tempting to stop taking your cephalexin after you start to feel better. This practice is generally not recommended and should be avoided. Remember that your doctor has prescribed you this medication for the duration of treatment because he/she followed some already proven evidence that doing so will help get rid of your infection. One of the many risks of not taking your cephalexin as prescribed, or any other antibiotics for that matter, is the risk of developing a resistant bug due to low levels of cephalexin in your body. This may then make you sicker and a little harder or challenging to treat the subsequent infection.

We discovered that my child has severe allergies to amoxicillin. I was wondering if he will be able to take cephalexin.

Amoxicillin and cephalexin belong to a class of medicine commonly referred to as beta lactams. Their chemical structures are similar and they are often prescribed by physicians to treat similar or related infections, with some notable few differences. Click chat now to be connected with a pharmacist for more.. Because these 2 are very similar in their chemical structures, the trial of cephalexin after a history of allergies to amoxicillin or penicillin will depend on the kind of allergic reactions patient had these medications. Patients who had prior minor allergic reactions to amoxicillin, such as rash or hives, are sometimes prescribed cephalexin due to documented low risk of cross-sensitivity. Pharmacists counsel such patients about the need to still monitor for allergic symptoms due to this risk.


Your son most likely will not be able to tolerate cephalexin if he had a severe allergic reaction to amoxicillin. Thus, discuss with your child’s pediatrician or pharmacists about this or any other allergies your son may have to medications.

Can I take OTC cold medicine like Advil cold and sinus while taking this medication?

Yes, if you are showing cold-like symptoms at the start of your cephalexin treatment, you may continue to take your over-the-counter cold medicines for symptoms relief. Over-the-counter cold medicines often contain anti-histamine, some pain reliever, and decongestants to help provide some relieve while the body (immune system) fights off the infection. Keep in mind that common cold is a viral infection and your cephalexin treatment will have no effect on the cold. It will, however, help treat the bacteria infection for which it was prescribed.

We have a 4 hours flight; do I have to keep my child’s Amoxicillin suspension cold?

The drug manufacturer recommends in the drug insert or label to keep the cephalexin suspension within a refrigerator range temperature. Also, from interacting with parents, most kids tend to prefer the taste of cephalexin suspension better when kept in the refrigerator or chilled. If possible, you may ask for cold water in a cup to keep the suspension chilled while on the plane. The amoxicillin suspension should be at a desirable temperature if carried on into the airplane for optimum efficacy. The general rule is that most medicines, regardless of their dosage forms, should not be exposed to or left in rooms or spaces with extreme temperatures. There may be a few exceptions to this rule. (Click the chat icon to be connected to a pharmacist). Most pharmacies are equipped with thermometers to measure the ambient temperature of the pharmacy in ensuring that medications are not exposed to extreme temperatures that may then affect how they work.


My Child takes daily probiotic; can I continue to give this to her while on amoxicillin?

Yes, you may continue to give your child the daily probiotic. It may help reduce some of the side effects from taking cephalexin, such as loose stools or diarrhea. There are few studies that support this practice and pharmacists routinely recommend this to their patients who may have had gastrointestinal side-effects from antibiotics. I always advise that parents avoid administering both together to their kids at the same time, but to separate them by couple of hours to allow for effectiveness of the 2 medications.



0 views0 comments