Skip to main content
Pets

Cephalexin for cats

Cephalexin treats bacterial infections in cats
SingleCare logo
By | Jul. 20, 2024 Medically reviewed by Emma Ryan, DVM
A grey cat sitting: Cephalexin for cats

Key takeaways

  • Cephalexin treats bacterial infections in cats, primarily skin and soft tissue infections.

  • The standard cephalexin dosage for cats is 15–35 mg/kg, taken by mouth every six to 12 hours.

  • The most common side effects of cephalexin in cats are fever and vomiting.

  • Do not give cephalexin to cats if the cat has ever had an allergic reaction to cephalosporin antibiotics.

  • Cephalosporin can be given with or without food. If the cat has digestive system problems, like vomiting, after a dose of cephalexin, give all further doses with food or a treat.

In this article:

Cephalexin is a common antibiotic used to treat bacterial infections. In veterinary medicine, the U.S. Food and Drug Administration has approved it for use in dogs, but cephalexin in cats is considered “off-label.” Although cephalexin is a broad-spectrum antibiotic, veterinarians primarily use it to treat skin or soft tissue infections. Cephalexin is a first-generation cephalosporin. These drugs kill bacteria by punching holes in their cell wall. Veterinarians can choose from various cephalosporins that work better than cephalexin for many other types of bacterial infections, so their use of cephalexin may be limited to skin and soft tissue infections. 

RELATED: Save up to 80% on cephalexin

What is cephalexin used for in cats?

Cephalexin treats some bacterial infections in cats, but veterinarians primarily use it for skin and soft tissue infections. They can also use it for other bacterial infections, such as urinary tract or respiratory tract infections, but they more commonly rely on other antibiotics for treatment. 

Skin infections

Veterinarians primarily use cephalexin to treat skin infections in cats or “pyoderma.” These infections are usually caused by bacteria called Staphylococcus. 

Pyoderma is the fifth most common skin disorder that veterinarians diagnose in cats. The bacteria causing the infection normally live on a cat’s skin without causing problems. However, if bacteria gets into broken or inflamed skin, it can create an infection. Getting the bacteria into the skin is usually caused by problems such as allergic reactions, follicle blockage, skin parasites like fleas or mites, hormone disorders, injury, immune suppression, or poor grooming.

Skin infections aren’t always easy to spot in a cat. The infected area may have hair loss, bumps, plaques, or sores. A deep infection might involve pus-filled bumps or skin wounds that won’t heal. 

Cephalexin and other first-generation cephalosporins are the drugs of choice for treating skin infections in cats. Some veterinarians start with topical antiseptics in the form of medicated shampoos or creams. These often work without causing significant side effects in the pet. If they don’t work or the infection is bad enough, a veterinarian will start the cat on oral antibiotics like cephalexin. 

Other infections

Veterinarians generally do not use cephalexin other than for bacterial skin infections in cats. Depending on the bacteria involved, they may use it for urinary tract or kidney infections. Veterinarians have a broad choice of antibiotics to treat UTIs in cats, so cephalexin is usually not the first choice.

Is cephalexin safe for cats?

Cephalexin is considered safe for cats and doesn’t usually cause side effects. When it does, these side effects tend to be minor. For this reason, veterinarians consider it a good choice for extended treatment of deep skin infections.

Cats allergic to cephalosporins should never be given cephalosporin because of the risk of a hypersensitivity reaction. Veterinarians are cautious about using it in cats allergic to penicillin, cefamycin, or carbapenem antibiotics because there’s a small risk they may be allergic to cephalosporins, too.

Tell the veterinarian if the cat has kidney disease, is pregnant or is lactating.

Side effects of cephalexin in cats

The most common side effects of cephalexin in cats are:

  • Vomiting
  • Fever
  • Diarrhea
  • Loss of appetite

These side effects are usually mild. However, call the veterinarian if they get worse or don’t go away.

Serious side effects of cephalexin in cats include:

  • Complete loss of appetite 
  • Severe allergic reactions
  • Severe skin reactions

Immediately call a veterinarian if you notice problems in the cat, such as:

  • Refusing to eat anything at all
  • Rashes, fever, trouble breathing, or weakness
  • Excessive grooming, excessive scratching, skin bumps, red or bright red skin, blisters, scales, skin plaque, pus-filled bumps, hives, swelling, rash 

Interactions of cephalexin with other pet meds

Before the veterinarian prescribes an antibiotic, make sure to tell the veterinarian about all the drugs, vitamins, and supplements the cat takes.

Cephalexin has very few drug interactions. The only drug that causes significant concern is probenecid, a gout treatment. Veterinarians may need to reduce the cephalexin dose or monitor for side effects.

Cephalexin dosage for cats

Cephalexin is used off-label in cats, so dosages might vary. 

For cats, the Merck Veterinary Manual recommends a standard cephalexin dosage of 15–35 mg/kg taken by mouth every six to 12 hours. Plumb’s Veterinary Drug Manual suggests a standard cephalexin dosage of 22 mg/kg of body weight administered every six hours.

Recommended cephalexin dosages for individual conditions in cats include:

  • For skin and soft tissue infections: 22-35 mg/kg administered every 12 hours (treatment should last for five to seven days after the infection resolves) 
  • For urinary tract infections: 12-25 mg/kg administered every 12 hours
  • For other susceptible infections: 10-15mg/kg is administered every six to eight hours

Pet parents can purchase human versions of cephalexin or use capsules or oral suspension formulations prepared by a compounding pharmacy in doses appropriate for a cat. Human versions come in 250 mg, 500 mg, and 750 mg capsules. These are too much for a cat, but there are human versions of cephalexin oral suspension that can be dosed in small amounts. Chewable tablets for dogs sold under the brand name Rilexine are also available, but the lowest dosage strength (150 mg) might be too high for many cats.

Can cats overdose on cephalexin?

Veterinarians have not standardized a maximum dose of cephalexin for cats. An overdose is most likely to cause side effects like vomiting or other gastrointestinal issues. Extremely high doses can cause serious problems such as kidney damage, nerve damage, liver damage, and blood problems such as low white blood cell counts or bleeding issues (thrombocytopenia).

If an overdose is suspected, call a veterinarian or emergency veterinary hospital for advice.

Can I give my cat cephalexin every day?

Cephalexin is a daily treatment. Pet parents give their cat two, three, or four doses a day for several days running. Symptoms should resolve in a couple of days, but it’s important to keep giving the cat this medicine to ensure the infection is fully eradicated. 

Expect to give the cat daily doses for skin infections for three weeks. Severe skin infections might require eight to 12 weeks of daily cephalexin. Side effects should be minimal if given at the prescribed dose.

How to give your cat cephalexin

Like with all antibiotics, it’s important that your cat gets every dose on time for the full duration prescribed. If doses are missed or discontinued prematurely, the infection may recur or develop resistance to antibiotics. 

To administer cephalexin to a cat:

  • Follow all the veterinarian’s instructions. 
  • Do not change the dose or dosing schedule. 
  • This medicine may be prescribed for several weeks. Ensure you understand how long you need to give the cat this medicine.
  • Do not miss doses. If a dose is missed, give the dose as soon as it’s remembered unless it’s almost time to give the next dose. In that case, skip the missed dose and give the next dose on time. Do not double up the dose if a dose is missed.
  • Cephalexin can be administered with or without food.
    • If the cat vomits or has digestive problems after a dose, try giving the dose with food or a treat.

How to administer cephalexin capsules:

  • A veterinary technician or other veterinary professional can demonstrate the proper technique to administer a capsule to a cat.
  • Store cephalexin capsules at room temperature

How to administer cephalexin oral suspension:

  • Shake the bottle well before measuring each dose. 
  • Use a calibrated oral syringe or other measuring device supplied by the veterinarian to measure doses. 
  • If you don’t know the proper technique for administering liquid medicine to a cat, ask a veterinary professional to demonstrate.
  • Store cephalexin oral suspension in the refrigerator. Throw it away 14 days after it was mixed.

Cephalexin alternatives for cats

Veterinarians primarily use cephalexin to treat skin infections in cats.

Some veterinarians choose to start with topical antimicrobials rather than oral drugs. They may be enough to eradicate the infection without the need for pills. Topical antiseptic treatments for cats come as medicated shampoos, mousses, creams, or gels with bacteria-killing active ingredients such as:

  • Chlorhexidine
  • Benzoyl peroxide
  • Ethyl lactate
  • Sodium hypochlorite

If these don’t work or the infection is more serious, veterinarians turn to systemic antibiotics. Their first choices are:

Any of these are suitable substitutes if cephalexin can’t be used or doesn’t work.

Summary

Veterinarians use cephalexin primarily to treat skin infections in cats. When given as directed by a veterinarian, cephalexin is safe for cats and usually doesn’t cause side effects. When it does, these side effects are usually minor. Although doses are given several times a day, cephalexin treatment can last a few weeks to a few months to eradicate the infection fully.

Sources