Veterinary 2025 Guide: Rilexine® (Cephalexin) for Skin & Urinary Infections 🐾🩺

Hello, I’m Dr Duncan Houston BVSc. This 2025 guide explores Rilexine®, a veterinary chewable formulation of cephalexin, a first-generation cephalosporin antibiotic commonly used in dogs and occasionally off-label in cats. We’ll dive into uses, dosing, side effects, monitoring, and how to support pet owners using the Ask A Vet platform 😊.

🔍 1. What Is Rilexine® (Cephalexin)?

Cephalexin is an oral beta-lactam antibiotic effective against many gram-positive (e.g., Staph pseudintermedius) and some gram-negative bacteria. Rilexine® provides a palatable chewable format designed specifically for dogs :contentReference[oaicite:3]{index=3}.

🎯 2. Indications

• Dogs: FDA-approved for superficial bacterial pyoderma (“hot spots,” itching, secondary staph infections) :contentReference[oaicite:4]{index=4}.
• Urinary Tract Infections: Commonly used off-label for UTIs in dogs—and sometimes cats—with supportive evidence :contentReference[oaicite:5]{index=5}.
• Cats: Extra-label use for similar skin and urinary infections when deemed appropriate :contentReference[oaicite:6]{index=6}.

💊 3. Dosing & Administration

• Recommended dose: 22 mg/kg (≈10 mg/lb) PO BID for 28 days to treat pyoderma, per label :contentReference[oaicite:7]{index=7}.
• Doses often range from 15–45 mg/kg every 6–12 hours depending on infection and culture results :contentReference[oaicite:8]{index=8}.
• Available in chewables (75/150/300/600 mg), capsules, and liquid suspension—shake well before use and dose with or without food :contentReference[oaicite:9]{index=9}.
• If a dose is missed, give it as soon as remembered unless it’s near the next dose—do **not** double-dose :contentReference[oaicite:10]{index=10}.
• Always complete the full prescribed course—even if the pet appears better—to prevent resistance :contentReference[oaicite:11]{index=11}.

⏱️ 4. Onset & Pharmacokinetics

Orally administered cephalexin is well absorbed, with therapeutic blood levels reached ~1–2 hrs after dosing. Excretion is primarily renal (~90% unchanged within 6–8 hrs) :contentReference[oaicite:12]{index=12}.

⚠️ 5. Potential Side Effects & Safety

• Common: mild GI issues—vomiting, diarrhea, inappetence, drooling, lethargy (<5%) :contentReference[oaicite:13]{index=13}.
• Rare but serious: allergic reactions (hives, breathing difficulty), blood changes (neutropenia, anemia), liver enzyme elevations :contentReference[oaicite:14]{index=14}.
• Reduce dose or extend interval in renal impairment; adjustments may be needed :contentReference[oaicite:15]{index=15}.
• Use cautiously in penicillin/cephalosporin-allergic pets and certain species (e.g. rabbits, rodents) :contentReference[oaicite:16]{index=16}.
• Avoid unsupervised use in pregnant/lactating animals—safety in this group has not been fully evaluated :contentReference[oaicite:17]{index=17}.

🔍 6. Monitoring & Follow-Up

• Assess clinical response within 3–5 days—look for decreased redness, itching, and improved wound closure.
• For UTIs, recheck via culture or urinalysis mid- to post-treatment to confirm clearance.
• In prolonged therapy (e.g., deep infections), monitor CBC, renal & liver function periodically.

📝 7. Drug Interactions & Considerations

• Probenecid slows elimination and may increase cephalexin levels :contentReference[oaicite:18]{index=18}.
• May reduce accuracy of some lab tests (e.g., urine protein, glucose, Coombs test)—alert your vet :contentReference[oaicite:19]{index=19}.
• No major drug interactions with most heart, thyroid, or respiratory medications—but always inform your vet of concurrent drugs :contentReference[oaicite:20]{index=20}.

📝 8. Client Education & Home Care

• Explain that Rilexine® is flavored and may be taken with meals to ease administration.
• Demonstrate proper measuring of liquid and splitting chewables if needed.
• Warn clients to watch for mild GI upset and report more severe or persistent issues.
• Stress importance of completing the full course—even if symptoms resolve early.
• Secure storage: keep medication away from children, other pets, and in pet-resistant containers.
• Recommend using the Ask A Vet app for dose reminders, side-effect logs, recheck alerts, and 24/7 veterinary messaging 😊.

📌 9. 2025 Vet Takeaways

• Rilexine® (cephalexin) remains a top choice for canine pyoderma and UTIs; off-label feline use is common under guidance.
• Dose at 22 mg/kg BID for skin infections; adjust by culture or renal function.
• Monitor response, GI signs, and lab values, especially with longer courses.
• Educate clients on dosing accuracy, side effects, and antimicrobial stewardship.
• Integration with Ask A Vet digital tools enhances compliance and safety 😊.

At Ask A Vet, we provide medication reminders, treatment trackers, lab-alert tools, and 24/7 vet messaging to support safe, effective antibiotic use. Encourage clients to download our app for confident, compliant care ❤️