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Cephalexin (Keflex) for Dogs

Cephalexin is a first-generation cephalosporin antibiotic used in dogs at 15–30 mg/kg. It treats skin, urinary, and respiratory infections.

Concept Fundamentals
15–30 mg/kg
Dose Range
BID–TID
Frequency
7–14 days
Duration
Cephalosporin
Class
Calculate Cephalexin DoseWeight-based antibiotic dosing

Why This Biology Metric Matters

Why: Accurate dosing ensures effective treatment of bacterial infections without toxicity.

How: Standard range: 15–30 mg/kg PO every 8–12 hours. Higher end for severe infections. Complete full course.

  • ●First-generation cephalosporin; effective against many Gram-positive bacteria.
  • ●Give with food to reduce GI upset.
  • ●Do not use in dogs with known penicillin/cephalosporin allergy.
Sources:Merck Veterinary ManualPlumb's Veterinary Drug Handbook

Calculate Cephalexin dosage for dogs. Weight-based dosing for skin, UTI, respiratory, and other bacterial infections.

Compact Examples

Small Dog - Skin Infection

12 lb Yorkie with skin infection

Medium Dog - UTI

40 lb Cocker Spaniel with UTI

Large Dog - Wound Infection

65 lb Golden Retriever with wound infection

Puppy - Respiratory Infection

15 lb puppy with respiratory infection

Enter Dog Information

🐕 Dog Weight

Enter your dog's weight

💊 Medication Form

🏥 Treatment Details

For educational use only. Always confirm dosages and care with a licensed veterinarian.

🧬 Biology Facts

💊

Cephalexin is a beta-lactam antibiotic in the cephalosporin class.

— Pharmacology

🦠

Effective against Staphylococcus, Streptococcus, and some E. coli.

— Spectrum

⏱️

Typically given BID (every 12 hr) or TID (every 8 hr).

— Dosing

📋

Complete the full course even if symptoms improve.

— Compliance

📋 Key Takeaways

  • • 10–15 mg per pound (22–33 mg/kg) per dose. Twice daily typical.
  • • Effective for skin, UTI, respiratory, wound, dental infections in dogs.
  • • Requires veterinary prescription. Complete full course even if symptoms improve.
  • • Give with food. Kidney disease may require dose adjustment.

💡 Did You Know?

💊Cephalexin (Keflex) is a first-generation cephalosporin. Effective against many bacterial infections.Source: Vet med
🐕Dose range 10–15 mg/lb. Dogs vary widely in size—always weigh and calculate.Source: Canine dosing
🔬Works by disrupting bacterial cell wall synthesis. Bactericidal—kills bacteria.Source: Antibiotic mechanism
⏱️Most dogs improve within 24–48 hours. Still complete full 7–14 day course.Source: Treatment timeline
🩺Kidney disease may require dose adjustment. Inform your veterinarian.Source: Renal clearance
🍽️Give with food to reduce stomach upset and improve absorption.Source: Administration

📖 How Cephalexin Dosing Works

Dose is based on dog weight. Standard range: 10–15 mg per pound per administration, typically every 8–12 hours.

Formula

Dose (mg) = Weight (lbs) × 10–15 mg/lb

Example: 25 lb dog → 250–375 mg per dose. Use 250 mg or 500 mg capsule.

🎯 Expert Tips

💡 Complete Full Course

Never stop early. Stopping can cause resistance and recurrence.

💡 Give with Food

Reduces stomach upset. Mix powder in wet food if needed.

💡 Kidney Function

Inform vet about kidney disease. Dose may need adjustment.

💡 Vet Prescription Only

Never use human meds or adjust dose without vet guidance.

⚖️ Dosage by Weight

WeightDose/AdminFrequency
5–10 lbs50–150 mgq8–12h
11–25 lbs110–375 mgq8–12h
26–50 lbs260–750 mgq8–12h
51–100 lbs510–1500 mgq8–12h

❓ Frequently Asked Questions

How long until Cephalexin works?

Most dogs improve in 24–48 hours. Complete full course (7–14 days) even if better.

Can I give human Cephalexin to my dog?

No. Never without vet guidance. Dosages differ; vet must determine treatment.

What if I miss a dose?

Give when remembered. If near next dose, skip missed. Never double dose.

Can puppies take Cephalexin?

Yes, with vet-calculated dose based on weight and age.

Dog vomited after dose?

If within 30 min, may re-administer. If persistent, contact vet.

How to store?

Capsules: room temp. Liquid: refrigerate. Discard after expiration.

📊 Cephalexin by the Numbers

10–15
mg/lb per dose
q8–12h
Typical frequency
7–14
Days typical course
24–48h
Improvement often seen

⚠️ Disclaimer: Educational only. Cephalexin requires a veterinary prescription. Always consult your vet. Never use human meds or adjust doses without vet guidance.

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