🐶💊 Cephalexin for Dogs: Vet-Approved Guide to Keflex Use in 2025

By Dr Duncan Houston BVSc

When your dog is dealing with a bacterial infection—especially those affecting the skin, urinary system, or wounds—your vet may prescribe a commonly used antibiotic called Cephalexin. This medication, known by its brand name Keflex, is a trusted first-line treatment for a wide variety of canine infections. 🦠🐾

In this detailed 2025 veterinary guide, you’ll learn how Cephalexin works, what it treats, potential side effects, and best practices for safe, effective use. Let’s dig in! 📘🐶

🔬 What Is Cephalexin?

Cephalexin is a first-generation cephalosporin antibiotic used widely in veterinary medicine. Like penicillin, it is a bactericidal antibiotic, meaning it kills bacteria directly by disrupting their cell walls. But unlike penicillin, Cephalexin is effective even against many bacteria that have become resistant to older antibiotics. 🧬💪

It works especially well against Gram-positive bacteria, such as:

• Staphylococcus – common in skin and wound infections
• Streptococcus – often associated with respiratory and soft tissue infections

Some Gram-negative bacteria are also susceptible, but more advanced cephalosporins or other antibiotic classes may be needed for serious Gram-negative infections. 🔬

📦 Available Forms

Cephalexin is available in a wide range of dosage forms to fit your dog’s size, taste preferences, and health condition:

• Capsules: 250 mg, 333 mg, 500 mg, 700 mg, 750 mg 💊
• Chewable tablets: 75 mg, 150 mg, 300 mg, 600 mg 🦴
• Non-chewable tablets: 250 mg and 500 mg 💊
• Oral suspension (liquid): for small dogs or picky eaters 🍼

💡 Why It’s Commonly Prescribed

Cephalexin is a broad-spectrum antibiotic, making it effective for a variety of uncomplicated infections. It’s often prescribed for:

• Pyoderma – a bacterial skin infection common in dogs 🐕‍🦺
• Hot spots – red, inflamed skin lesions 🔥
• Post-surgical wound infections 🩹
• Urinary tract infections (UTIs) 💧
• Respiratory infections 🌬️

It’s often chosen for long-term therapy (6 to 8 weeks) due to its well-established safety profile. 💯

⏱️ Dosing & Administration

Cephalexin is typically given two to three times daily. Your vet will determine the dosage based on your dog’s weight, the infection being treated, and response to the drug.

Tips for success:

• Can be given with or without food (food may reduce nausea) 🍽️
• If a dose is missed, give it as soon as you remember—but don’t double up
• Finish the full course—even if your dog seems better mid-treatment ✅

❄️ Storage Guidelines

Proper storage helps preserve medication potency:

• Capsules/tablets: Store at room temperature away from direct light 🌡️
• Oral suspension: Refrigerate and use within 14 days ❄️🧪

⚠️ Side Effects to Watch For

Most dogs tolerate Cephalexin well, but some side effects may occur:

• Nausea or vomiting – most common, usually eased with food 🤢
• Diarrhea – mild and often temporary 💩
• Excessive drooling or hyperactivity – rare but possible 🐶⚡
• Fever in cats – a less common reaction 🐱🌡️

Call your vet if your dog exhibits unusual behavior, severe gastrointestinal upset, or signs of allergic reaction like hives or facial swelling. 📞🆘

💊 Drug Interactions

Cephalexin is sometimes used in combination with other antibiotics in serious infections, but caution is needed if your dog is on:

• Omeprazole (Prilosec) – can increase cephalexin absorption
• Metoclopramide – may elevate cephalexin levels in the body

Always inform your vet about all supplements, vitamins, or meds your pet is taking. 🧾

👶 Use in Puppies and Pregnant Dogs

Cephalexin is considered safe for long-term use—even in puppies—but some extra caution applies:

• Pregnancy: Avoid use unless no alternative exists, as it crosses the placenta
• Lactation: Does not pass into milk in significant amounts—likely safe for nursing moms 🍼

🧪 Lab Test Interference

Cephalexin can sometimes cause false positives for glucose on urine dipsticks. If your pet is diabetic or undergoing routine urine screening, let your vet know they’re on this medication. 🧫🔍

📲 When to Call the Vet

Call your veterinarian if you notice:

• Persistent vomiting or diarrhea 💩🤮
• Unusual behavior (agitation, drooling, tremors) 😬
• Signs of allergic reaction (facial swelling, hives, difficulty breathing) 🆘

📱 Simplify Treatment with Ask A Vet

Need help understanding your pet’s prescription? Download the Ask A Vet app to connect instantly with a licensed veterinarian. 🐾💬

Whether it’s midnight nausea or dosage confusion, Ask A Vet has you covered—24/7 support for all pet parents. 🐶📲

✅ Final Thoughts

Cephalexin (Keflex) remains a trusted, go-to antibiotic for veterinarians treating skin, wound, and urinary infections in dogs. It’s safe, well-tolerated, and flexible for both short-term and long-term use. 💊🐾

As always, follow your vet’s instructions carefully, complete the full course of medication, and keep a close eye on your pet’s response. With proper care, your pup will be back to their happy, healthy self in no time! 🐕❤️

– Dr Duncan Houston BVSc

💡Need more help with dog medications or infections? Visit AskAVet.com or download the Ask A Vet app today!