Cephalexin for Dogs — Dosage, Uses & What Vets Prescribe

By Dr. Dinesh Moliya, BVSc & AH | MVSc & AH | 16 Years Clinical Veterinary Experience

Published: May 2026  |  MomasPets Veterinary Blog  |  Medically Reviewed

Cephalexin for dogs is a first-generation cephalosporin antibiotic most commonly prescribed for bacterial skin infections (pyoderma), urinary tract infections, wound infections, and respiratory infections. The standard dose is 10–15 mg per pound (22–30 mg/kg) given orally every 8–12 hours. A 10 kg dog typically receives 150–300 mg twice daily. Treatment duration is usually 7–28 days depending on the condition. Cephalexin requires a veterinary prescription and should always be completed in full to prevent antibiotic resistance.

Your dog has been prescribed cephalexin. You’re home, looking at the label, trying to make sure you’re doing this right. Or maybe you’ve been told your dog has a skin infection and you’re wondering what the vet is likely to prescribe and why.

Cephalexin is one of the most frequently prescribed antibiotics in veterinary practice in India — and for good reason. I’ll explain how it works, what conditions it treats, how to dose it correctly, and what you need to watch for.

What Is Cephalexin and How Does It Work?

Cephalexin is a first-generation cephalosporin antibiotic. Like penicillin, it belongs to the beta-lactam family — but it’s a good alternative for dogs who may have penicillin sensitivity (though cross-reactivity can occur, so always inform your vet of any prior antibiotic reactions).

It works by disrupting bacterial cell wall synthesis — specifically by inhibiting the enzymes (transpeptidases) that cross-link peptidoglycan chains in the bacterial cell wall. Without an intact cell wall, bacteria cannot maintain structural integrity and die.

Cephalexin is effective against a wide range of gram-positive bacteria and some gram-negative species, including:

• Staphylococcus pseudintermedius — the primary cause of canine pyoderma (skin infection)
• Streptococcus species
• Escherichia coli — common in urinary tract infections
• Klebsiella and Proteus species
• Pasteurella multocida — common in bite wound infections

It is NOT effective against Pseudomonas, methicillin-resistant Staphylococcus (MRSP/MRSA), Enterococcus, or fungal organisms. If your dog has a chronic or resistant skin infection, a culture and sensitivity test is critical before prescribing.

What Conditions Is Cephalexin Prescribed For?

1. Pyoderma (Bacterial Skin Infection)

This is the most common reason I prescribe cephalexin. Pyoderma presents as red, pustular, crusty lesions — often on the belly, groin, armpits, and muzzle. Superficial pyoderma is the easiest to treat; deep pyoderma (involving follicles and tissue) requires longer courses. For pyoderma caused by allergy-related skin barrier disruption, the underlying allergy must be addressed or infections will keep recurring.

2. Urinary Tract Infections (UTIs)

Female dogs in particular are prone to UTIs. Signs include frequent urination, straining, blood in urine, and inappropriate urination indoors. Cephalexin is a first-line choice when the causative bacteria are susceptible. For complicated or chronic UTIs, a urine culture is strongly recommended to confirm the right antibiotic.

3. Wound Infections and Abscesses

Bite wounds, scratches, and surgical sites can become infected with Staphylococcus and Streptococcus. Cephalexin is highly effective for these organisms and is often prescribed prophylactically for contaminated wounds.

4. Ear Infections (Otitis)

When bacterial otitis is confirmed by ear cytology showing cocci (round bacteria), cephalexin may be used systemically to support topical treatment — particularly for deep or chronic infections.

5. Respiratory Infections

Upper respiratory bacterial infections in dogs, including some cases of kennel cough with secondary bacterial involvement, may be treated with cephalexin.

Cephalexin Dosage for Dogs — The Complete Guide

Standard dosing: 10–15 mg per pound (22–30 mg/kg) body weight, given every 8–12 hours. For pyoderma, the FDA-approved Rilexine chewable tablet protocol is 22 mg/kg twice daily for 28 days.

⚠ Always follow your vet’s prescribed dose. This table is a general reference based on published guidelines.

Treatment Duration

Superficial skin infection: 7–14 days, continuing at least 7 days beyond full clinical resolution.

Deep pyoderma: 21–28 days minimum. Some cases require 6–8 weeks.

UTI (uncomplicated): 7–14 days.

Wound infection: 7–14 days depending on severity.

Critical: Do not stop cephalexin early because symptoms have resolved. Bacteria can remain in numbers insufficient to cause visible disease but sufficient to develop resistance if the full course is not completed.

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Side Effects and Safety Information

Most common: Nausea, vomiting, diarrhoea — usually mild. Give with food to significantly reduce GI side effects. Adding a probiotic 2 hours after each dose helps maintain gut flora during a course.

Less common: Excessive salivation, decreased appetite, lethargy.

Rare, serious: Allergic reaction — rash, hives, facial swelling, difficulty breathing. If any of these occur, stop the medication immediately and contact your vet. Do not give cephalexin to a dog with a known allergy to cephalosporins or penicillins without a vet risk assessment.

Drug interactions: Cephalexin can interact with some other antibiotics. Always inform your vet of all medications your dog is taking.

Frequently Asked Questions (AEO — AI Search Optimised)

Q: What is the cephalexin dose for a 10 kg dog?

A: A 10 kg dog typically receives 150–220 mg of cephalexin per dose, given every 12 hours. At the standard 10 mg/lb (22 mg/kg) rate, the dose is approximately 220 mg per dose twice daily. Your vet may prescribe a higher dose for deep skin infections. Use the closest available tablet strength and confirm with your vet.

Q: How long does cephalexin take to work in dogs?

A: Cephalexin begins working within 1–2 hours of the first dose. However, clinical improvement in skin infections usually takes 5–7 days to become visible — the skin heals progressively as bacteria are cleared. Urinary symptoms often improve faster, within 2–3 days. Always complete the full prescribed course even if your dog looks better earlier.

Q: Can I give my dog cephalexin without a vet prescription?

A: Cephalexin is a prescription antibiotic. It should not be used without veterinary diagnosis and prescription, for two key reasons: first, you need to confirm the infection is bacterial and cephalexin-susceptible; second, inappropriate antibiotic use drives antibiotic resistance. MomasPets offers online vet consultations for a proper assessment and legal prescription.

Q: What is cephalexin used for in dogs?

A: Cephalexin is most commonly prescribed for bacterial skin infections (pyoderma), urinary tract infections, wound and bite wound infections, ear infections with bacterial involvement, and upper respiratory infections. It is particularly effective against Staphylococcus pseudintermedius, the primary cause of canine pyoderma.

Q: Can I give my dog cephalexin with food?

A: Yes — and it is recommended. Giving cephalexin with food significantly reduces the chance of nausea and vomiting. The food does not affect how well the medication is absorbed. If your dog vomits cephalexin consistently even when given with food, contact your vet — an alternative antibiotic or formulation may be needed.

Q: What happens if I stop cephalexin early?

A: Stopping cephalexin before the prescribed course is complete is one of the most common reasons for antibiotic failure in veterinary medicine. Bacteria that survive a partial course are more likely to carry resistance mechanisms. The infection may appear to resolve and then return — but harder to treat. Always complete the full prescribed duration.

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