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Cephalexin for Dogs

by Lilly

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Cephalexin for Dogs

Cephalexin is a broad-spectrum antibiotic for your dog and as a veterinary medicine, it goes under the trade names of Cefalexin, Keflex, Rilexine, Sporidex, and Biocef. It treats a wide range of bacterial infections, dog urinary tract infections, kidney disease, and respiratory tract infections that can affect your dog’s health at any age. Veterinarians regularly prescribe Cephalexin to treat bacterial issues or to ward off the threat of infection. Cephalexin treats the following type of infections:

  • Skin
  • Urinary tract
  • Ear
  • Joint
  • Respiratory tract

Cephalexin is also used to prevent infection of the heart valves and is often prescribed to prevent infections from open wounds or abscess. S. Aureus bacteria is quite often found in skin infections or “hot spots,” which can occur due to allergies. Cephalexin is an option for treatment in these cases. However, these types of infections also mean that there may be other treatments added on to Cephalexin to help your pup feel better. Medicated shampoos or allergy medications may help in the long-term if they do not negatively interact with Cephalexin.

As with any product you give to your dog, make sure you check with your dog’s veterinarian before using it. In this case, a prescription is needed as you are either treating or preventing what could be a significant infection that needs to be stopped.

Why Would My Dog Need Cephalexin?

Your dog would need Cephalexin if he had some type of bacterial infection. This medication works well against active gram-positive bacteria and moderately well against active gram-negative bacteria. Once the veterinarian takes skin scrapings and/or a blood test from your dog, they can begin to understand the bacteria that is causing the issue. Knowing the bacteria means they can choose a medication that is the most effective in curing it. Often, Cephalexin is the right drug to take care of the infection and eliminate the offending bacteria. Cephalexin is also needed if your pup has been infected by the following:

  • E. coli
  • Haemophilus influenza
  • Klebsiella pneumonia
  • Proteus mirabilis
  • Streptococcus pneumonia
  • Streptococcus pyogenes

Again, this is not a drug to be taken without the proper testing and direction by your dog’s veterinarian. The drug itself is not as much of an issue as monitoring the underlying infection is. If the type of infection is not clear, then the drug may not be effective. This wastes time and resources and offers little help to your dog.

When Shouldn’t My Dog Take Cephalexin?

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Your pup should not be taking Cephalexin if the bacteria that is infecting them is anaerobic. These are basically organisms that grow without oxygen. Your veterinarian will prescribe penicillin for those. It should also not be taken if the infection is Enterobacter bacterium. This often causes canine skin, urinary tract and eye infections and Cephalexin will not work. It could build up drug resistance which means your pup may not respond properly when Cephalexin is actually needed. It is also important to note this drug will not work against viruses or fungal infections (bacterial only). Your dog should also not take Cephalexin if they are:

  • Pregnant
  • Have kidney failure
  • Epileptic
  • Have had a seizure
  • React to penicillin
  • React to any antibiotics

How Does My Dog Take Cephalexin?


Cephalexin for dogs comes in liquid, pill, or capsule form. It is measured in milligrams and the amount is determined on body weight and what they have been diagnosed with. It is usually prescribed to be given two to three times per day at the same time every day so the amount in their system stays consistent. It is the consistency of taking a dose every six to eight hours that makes the drug successful. A prescribed treatment dosage will last from seven to ten days. Your pup’s veterinarian will also look at any underlying conditions that may preclude them from taking it or perhaps require a dosage adjustment. If you happen to miss giving your pup a dose or are very late then just give the current dose as soon as possible but do not double up on the amounts.

Cephalexin Side Effects in Dogs

Cephalexin is not generally prescribed for long-term use. If this is the case, then your veterinarian will be monitoring your pup for kidney or liver issues. Long-term use may also create a significant drop in their blood platelet counts. However, in short-term use, side effects are not overly prevalent. That being said, as with any drug, side effects are possible and need to be monitored. Gastrointestinal side effects can often be tempered by taking it with food and will disappear if addressed properly. Some of the side effects may be:

  • Nausea
  • Vomiting
  • Diarrhea
  • Drooling
  • Hyper-excitability
  • Excess panting

Like any pet owner, it’s important not only to know the possible side effects of a new medication but when to talk to a vet about issues you see arising and or are concerned about. A veterinary check-in is important, especially near the end of the antibiotic treatment to make sure whatever infection was present has gone. If the treatment cycle is cut short or has not been fully effective, then there is a threat that the infection will rebound and send your dog back to the initial stages of their infection. This will mean another round of treatment for what could be a progressively worsening issue.


Cephalexin is not yet an FDA-approved animal drug, but it is a safe medication when instructions are followed. As with the introduction of any supplement or medication, it’s important to keep your veterinarian in the loop to make sure it’s used in a safe and helpful way to your pup. This is even more important as you are dealing with infections that can be deadly to your dog if they are not medicated properly. It is critical to not only heal his infections but to make sure he is able to feel better and more comfortable being infection-free.