Cephalexin

Updated on September 10, 2024

First generation cephalosporin antibiotic used to treat a variety of susceptible bacterial infections.

Cephalexin

Summary

Used For: Susceptible infections of the skin and urinary tract

Brands: Keflex®

Species: Dogs, cats, horses, rabbits (use with caution), small mammals (use with caution), ferrets, birds and reptiles

Other names: Keflex®, Rilexine®

Drug type: Antibiotic

Prescription required: Yes

Pregnancy and lactation: Safety in pregnancy and lactation has not been evaluated

Side effects: Gastrointestinal upset

General description

Cephalexin is a first generation cephalosporin antibiotic used to treat susceptible infections. It provides excellent coverage against most gram-positive and anaerobic bacteria. [Buy Cephalexin now on Petco.](https://www.petco.com/shop/en/petcostore/brand/cephalexin) A prescription from your veterinarian may be needed to purchase.

Uses

Labeled for use in dogs to treat superficial bacterial skin infections, but used extra-label to treat susceptible urinary tract infections and other infections.

How it works

Cephalexin is a cephalosporin antibiotic that damages the protein production in the cell wall of bacteria, causing ultimate death of the infectious bacteria. Cephalexin is effective against most gram-positive and anaerobic bacteria, but is generally ineffective against most gram-negative bacteria.

Dosage

Dosing is only labeled with Rilexine® for treatment of skin infections in dogs. All other prescribed uses are considered extra-label (non FDA-approved). **Dogs:** Labeled dose: 22 milligrams per kilogram by mouth every 12 hours for 28 days. Extra-label dose: 22-40 milligrams per kilogram by mouth every 12-24 hours **Cats:** 22-30 milligrams per kilogram by mouth every 12 hours **Rabbits:** 15 milligrams per kilogram subcutaneously every 12 hours. Oral administration is not recommended **Guinea pigs:** 50 milligrams per kilogram intramuscularly every 24 hours **Ferrets:** 15-25 milligrams per kilogram by mouth every 8-12 hours **Reptiles:** 20-40 milligrams per kilogram by mouth every 12 to 24 hours **Birds:** 35-100 milligrams per kilogram by mouth every 6-8hours (using liquid suspension) **Foals:** 30 milligrams per kilogram by mouth every 12 hours.

Forms

Rilexine® chewable tablets for oral use available in 75 milligrams, 150 milligrams, 300 milligrams & 600 milligrams; generic oral capsules available in 250 milligrams, 333 milligrams, 500 milligrams & 750 milligrams; generic oral tablets available in 250 milligrams & 500 milligrams; powder for oral suspension available in 125 milligrams per 5 milliliters & 250 milligrams per 5 milliliters

Storage information & handling

Tablets and capsules: Keep dry and store at room temperature in a tightly sealed container; Liquid suspensions: Shelf stable for up to 2 weeks after reconstitution. Store in a tightly sealed container at room temperature.

What results can I expect?

With proper administration, resolution of clinical infection should result. Give entire the prescribed dose and do not stop the medication early, even if clinical signs seem to have resolved.

Missed Dosage

If a dose is missed, continue with the next dosage at the scheduled time.

Overdose / acute toxicity

Overdoses can lead to gastrointestinal effects (anorexia, vomiting, diarrhea) and typically do not require treatment.

Side effects

* Gastrointestinal upset (decreased or absent appetite, vomiting, diarrhea) * Hypersensitivity reactions (anaphylaxis, lymph node enlargement, fever, rashes)-rare * Serious skin reactions (toxic epidermal necrolysis, erythema multiforme, cutaneous vasculitis) - rare * Nephrotoxicity - rare * Severe enterocolitis is possible in rabbits, guinea pigs, hamsters, gerbils, and other small rodents

Contraindications

* Use with caution in patients with renal disease * Contraindicated in patients allergic to cephalosporins * Use with caution in patients hypersensitive to other beta-lactam antibiotics (such as penicillins)

Drug interactions

The uric acid-reducing drug, Probenecid, increases the serum level and serum half-lives of cephalexin.

Precaution

May cause severe enterocolitis in small mammals. Safety has not been evaluated in pregnant and lactating animals.

Sources

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Disclaimer

The information contained on this page is for educational purposes only. This medication should only be given under the advice of a veterinarian who has examined your pet under the laws applicable to your state of residence.