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PetDosageChart

Amoxil (Amoxicillin) Dosage for Cats

Antibiotic (Penicillin) ⏱ Onset: 1-2 hours ⏳ Duration: 8-12 hours

This dosage information is for educational purposes only. Always consult your veterinarian before giving any medication to your pet. Dosages may vary based on your pet's health conditions, other medications, and individual factors.

Content reviewed by licensed veterinarians. This information is sourced from veterinary drug references including Plumb's Veterinary Drug Handbook and the Merck Veterinary Manual.

Dosage Calculator

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Amoxil Dosage Chart for Cats by Weight

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Weight Low Dose Standard Dose Max Dose Frequency
3 lbs (1.4 kg) 7mg 14mg 35mg every 8-12 hours
4 lbs (1.8 kg) 9mg 18mg 45mg (50mg tablet) every 8-12 hours
5 lbs (2.3 kg) 11.5mg 23mg 57.5mg (50mg tablet) every 8-12 hours
6 lbs (2.7 kg) 13.5mg 27mg 67.5mg every 8-12 hours
7 lbs (3.2 kg) 16mg 32mg 80mg every 8-12 hours
8 lbs (3.6 kg) 18mg 36mg 90mg (2 × 50mg) every 8-12 hours
9 lbs (4.1 kg) 20.5mg 41mg (50mg tablet) 102.5mg (2 × 50mg) every 8-12 hours
10 lbs (4.5 kg) 22.5mg 45mg (50mg tablet) 112.5mg every 8-12 hours
12 lbs (5.4 kg) 27mg 54mg (50mg tablet) 135mg every 8-12 hours
14 lbs (6.3 kg) 31.5mg 63mg 157.5mg (3 × 50mg) every 8-12 hours
16 lbs (7.3 kg) 36.5mg 73mg 182.5mg every 8-12 hours
18 lbs (8.2 kg) 41mg (50mg tablet) 82mg 205mg (4 × 50mg) every 8-12 hours
20 lbs (9.1 kg) 45.5mg (50mg tablet) 91mg (2 × 50mg) 227.5mg every 8-12 hours
25 lbs (11.3 kg) 56.5mg (50mg tablet) 113mg 282.5mg every 8-12 hours

What is Amoxil (Amoxicillin) used for in cats?

bacterial infections skin infections urinary tract infections upper respiratory infections dental infections

How to give Amoxil to your cat

The liquid suspension (often banana-flavored) is usually easiest for cats. Use a syringe to administer into the side of the mouth. Clavamox (amoxicillin/clavulanate) drops are commonly prescribed for cats and should be refrigerated. Complete the full course even if your cat seems better.

Available Forms

tablet, liquid suspension

Give with Food?

Yes — give with food

Side effects of Amoxil in cats

Common side effects

diarrhea
vomiting
decreased appetite
drooling

Serious side effects

  • allergic reaction (facial swelling, hives)
  • severe diarrhea
  • difficulty breathing

When to call the vet

Call your vet immediately if your cat shows any of these signs:

  • Signs of allergic reaction (facial swelling, difficulty breathing)
  • Severe or bloody diarrhea
  • Refusal to eat for more than 24 hours
  • No improvement after 48-72 hours
  • Vomiting after every dose

Related Medications for Cats

Fluoroquinolone antibiotic

Baytril

Enrofloxacin

For bacterial infections

View dosage chart
Antibiotic (Tetracycline)

Vibramycin

Doxycycline

For upper respiratory infections

View dosage chart
First-Generation Cephalosporin Antibiotic

Keflex

Cephalexin

For Skin and soft tissue infections

View dosage chart
Nitroimidazole Antibiotic / Antiprotozoal

Flagyl

Metronidazole

For Inflammatory bowel disease (IBD)

View dosage chart

Sources & References

The dosage information on this page is compiled from the following veterinary and pharmaceutical references:

  • Plumb's Veterinary Drug Handbook — the standard veterinary pharmacology reference used by veterinarians worldwide.
  • Merck Veterinary Manual — a trusted, peer-reviewed resource for veterinary professionals and pet owners.
  • DailyMed (FDA Drug Labels) — official FDA-approved drug labeling and prescribing information for Amoxicillin.

Frequently Asked Questions

Can I give my cat amoxicillin?
Amoxicillin is commonly prescribed for cats by veterinarians for various bacterial infections. However, you should never give your cat amoxicillin without a prescription — the vet needs to diagnose the infection, determine if an antibiotic is appropriate, and calculate the correct dose for your cat.
How much amoxicillin do I give my cat?
The typical dose for cats is 5-10 mg per kilogram of body weight, given every 12 hours. For an average 10 lb (4.5 kg) cat, this is approximately 45-90 mg per dose. The liquid suspension is easiest to dose accurately for cats.
What are the side effects of amoxicillin in cats?
The most common side effects in cats are digestive — diarrhea, vomiting, and decreased appetite. These are usually mild. Serious allergic reactions are rare but require immediate veterinary attention. Probiotics may help reduce GI side effects.
How long does a cat take amoxicillin?
A typical course is 7-14 days, depending on the infection type and severity. Upper respiratory infections may need 10-14 days. Always complete the full prescribed course to prevent antibiotic resistance, even if your cat appears better.

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