Major Uses

Cephalexin is an oral cephalosporin antibiotic used to treat a variety of infections in dogs and cats. The drug has a broad range of activity and works by inhibiting the growth of the bacteria cell well, resulting in bacteria death. Cephalexin may be prescribed to treat skin infections, wound infections, bone infections, pneumonia, or bladder infections.

Common Precautions

Side effects with the use of cephalexin are typically rare and mild. The most common effects animals may experience are stomach upset, loss of appetite, vomiting, and diarrhea. It has been shown that if a small meal is given with administration of the drug, these symptoms may subside. Some dogs may experience excessive panting, salivation, and excitability. It has also been reported that cats can run a fever with the use of cephalexin; a fever in cats is considered a temperature above 103° F. The pet's veterinarian should be contacted if these symptoms persist, as an alternate antibiotic may be necessary.

If given in high doses, the drug can cause damage to the kidneys so it should be used with extreme caution in patients in kidney failure. Cephalexin should also be used with caution in patients with epilepsy, or those that are pregnant or nursing. The drug should not be administered orally to patients with sepsis, shock, or any other serious diseases; intravenous administration is the recommended method in these cases. Because drug interactions are always a possibility, the prescribing veterinarian needs to be informed of all other medications the pet is taking prior to administration.

Cephalexin should not be administered to animals with a known allergy or hypersensitivity to the drug, other cephalosporins, or penicillins. An allergic reaction may manifest as rashes, fever, or anaphylaxis. Emergency care should be sought if any of these or other unusual reactions occur.


Cephalexin tablets and capsules should be stored at room temperature in childproof, light resistant containers. The oral suspension should be stored up to 14 days in the refrigerator.


Cephalexin is available in 250 mg and 500 mg tablets and capsules. It is also found in 125 mg/5mL and 250 mg/mL oral suspension. The typical dose for dogs and cats is 10 - 15 mg/lb (22 - 30 mg/kg) every 8 - 12 hours orally. Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.

If a dose is missed it should be given as soon as possible. If it is almost time for the next dose, the missed dose should be skipped and the regular schedule can proceed. Two doses should never be given at once as it can be toxic.

This information is for general reference only and should not be used for the diagnosis or treatment of any condition of your pet. It's intended as a general reference, this information may not include all possible uses, precautions, directions, reactions (including allergic), drug interactions, or withdrawal times. Always consult your local veterinarian and have your pet examined for any advice concerning the diagnosis and treatment of your pet, including which products and doses are most appropriate. Any trademarks are the property of their respective owners. VetDepot is not a pharmacy. All prescription products are dispensed by our Pharmacy Partner. Article last updated 2/2014.