What Every Dog and Cat Owner Should Know About Antibiotics
At Petscribers, we believe that knowledge is power, especially when it comes to your pet's health. As vets, one of the most common topics pet owners ask us about is antibiotics.
My animal is sick, why aren’t they being given antibiotics? Why do I need a vet to prescribe them? Why don’t they appear to be working?
Here’s everything you need to know about antibiotics for pets, written by vets, and made for pet owners.
What Are Antibiotics and When Are They Needed?
Antibiotics are medicines used to kill or inhibit the growth of bacteria. They are powerful tools when treating bacterial infections in dogs and cats, from infected wounds and skin infections to urinary tract infections and respiratory illnesses.
But here’s the thing: antibiotics only work on bacteria.
They do not treat viruses, fungi, or parasites and giving antibiotics when they’re not needed can do more harm than good. This is why it’s important to speak to your vet and have your dog or cat examined to determine if antibiotics are going to help your pet with their illness.
Common Conditions That May Require Antibiotics
- Skin infections (like hot spots or pyoderma)
- Ear infections with bacterial overgrowth
- Urinary tract infections confirmed by lab testing or microscopy
- Post-surgical wound infections
- Dental infections or abscesses
Your vet will often perform diagnostic tests (such as taking a swab to send for culture or examining samples under a microscope) to confirm the presence of a bacterial infection before prescribing antibiotics.
Why You Can’t Buy Pet Antibiotics Over the Counter in the UK
In the UK, all antibiotics for pets are prescription-only medicines. That means a vet must prescribe them following an in-person clinical assessment. This regulation exists to keep pets safe and prevent the rise of antibiotic-resistant infections.
We see lots of pet owners in the UK searching for “dog antibiotics without vet” or “cat antibiotics without vet prescription,” - so if you wondered this, you’re not alone. But here’s the truth: there is no safe or legal way to get antibiotics for pets without a vet examining your animal and prescribing them.
The Dangers of DIY Antibiotic Use
We know it’s tempting to use leftover antibiotics or human medications, like amoxicillin, on your pet. But we urge you against this because self-prescribing can:
- Lead to incorrect dosing (which can be dangerous for your beloved pet)
- Miss the real cause of illness (it might not be bacterial)
- Increase antibiotic resistance (making future infections harder to treat)
Even if it worked last time, it may not work this time. Your vet’s judgment is key.
Understanding ‘Antibiotic Resistance’
When antibiotics are overused or misused, bacteria can adapt and become resistant. These so-called “superbugs” are incredibly difficult to treat and pose a danger not just to pets, but to humans too.
That’s why vets take antibiotic use seriously. It’s essential to be cautious and responsible when using antibiotics and caring for your pets.
Commonly Prescribed Pet Antibiotics
Here are some of the most frequently prescribed types of antibiotics for dogs and cats in the UK:
- Penicillins
- Cephalosporins
- Antifolates and Sulfonamides (e.g. Trimethoprim/Sulfamethoxazole - TMPS)
- Tetracyclines (such as Doxycycline)
- Aminoglycosides (such as Gentamicin)
- Lincosamides (such as Clindamycin and Lincomycin)
- Fluoroquinolones (such as Enrofloxacin and Marbofloxacin)
- Macrolides (such as Erythromycin)
Each has a specific use, dose, and duration. Your vet will use their knowledge, experience and any test results to decide exactly what is the best prescription of antibiotics for your pet.
Side Effects to Watch For
While most pets tolerate antibiotics well, side effects of antibiotics can include:
- Upset stomach or vomiting
- Diarrhoea
- Lack of appetite
- Allergic reactions (though this is rare)
If your pet reacts badly to antibiotics, call your vet.
Sometimes, adding a prebiotic and/or probiotic, or adjusting the medication can help - but always consult with your vet first.
Your Role as a Pet Owner
- Follow dosage instructions exactly. Don’t skip or stop early, even if your pet appears to be better.
- Finish the course. Stopping early can leave some nasty bacteria behind that are more resistant to the antibiotic, making future treatment with that same antibiotic less effective.
- Never share antibiotics between pets or use human medications without your vet’s advice.
- Store antibiotics safely and never use expired medications. Check the instructions on the pack.
"Always follow dosing instructions carefully, and finish the whole course"
Antibiotics and Your Pet
Antibiotics save lives. But they must be used properly, at the right time, and in the right way.
If your dog or cat has a suspected infection, contact your vet. They’ll decide whether antibiotics are necessary and what type is most appropriate.
At Petscribers, we’re here to support pet owners in making informed, confident choices with vet-led tools that simplify the journey.
If you’re looking to understand more about your pet’s medication, browse our “Bite Size Meds” guides or speak with your vet. And remember: the safest medication is the one that’s prescribed with care.
Use our search engine to find antibiotics for cats or antibiotics for dogs.
Need a prescription? Ask your vet. Already have your prescription? Use Petscribers to compare UK-approved pharmacies and find trusted, affordable options, all in one place.
If you’ve been prescribed antibiotics for your pet, then you can use our medication search engine to find the product you need and compare government-approved suppliers based on cost, delivery speed and whether they are an independent provider or not.
Antibiotics Q&A:
Is it safe for my dog to be on antibiotics for the rest of his life?
We rarely see animals on antibiotics for life, except in cases of very rare conditions. If deemed necessary, your vet will be seeing you and your dog regularly for check-ups. At these check-ups, it should be possible to have regular discussions on new/alternative treatments that avoid the “antibiotics for life” scenario. Vets are very keen to protect the effectiveness of antibiotics, so if an alternative treatment has been developed, they would likely want to discuss this with you and see if you would like to explore this as an option for your pet.
What are the side effects of amoxicillin in pets?
Amoxicillin is generally well-tolerated, but some animals may experience mild side effects, which can include loss of appetite, diarrhoea and vomiting.
Allergic reactions are rare but can cause severe symptoms, including difficulty breathing, swelling, or hives. If this occurs, stop the medicine and contact your vet.
Occasional reports of colitis (inflammation of the colon, usually causing slimy or bloody soft poo/diarrhoea) and abnormalities in red/white blood cell counts are also listed as side-effects for certain brands.
How to treat an infected wound on a dog?
Wounds that are fresh and clean should be cleaned with cooled, boiled water and ideally assessed by a vet if they are anything more than a surface scratch or graze.
Sometimes, vets will use a dilute chlorhexidine solution to clean wounds and reduce the number of bacteria. This may be all that is required for a minor wound, and your veterinarian may dispense some of this for you to use at home.
However, if the wound is;
- “Dirty”; involving dirt/soil, a bite wound, or where the object inflicting the wound was dirty, e.g. rusty barbed wire, or a glass fragment.
- Deep
- Near vital structures (e.g. near a joint)
- Or an infection has already taken hold
Antibiotic cream or tablets may be necessary, and the wound should definitely be looked at by a vet.
Can I put antibiotic ointment on my dog?
Not unless it’s been prescribed by your vet.
Can you give a dog human amoxicillin 500mg?
No, this is a human dose of medication.
As humans all have relatively standard organ sizes, the dose of medication could be the same regardless of whether we are tall, short, male, or female. Our pets can have a much wider variation in body types - think of a Great Dane vs. a Chihuahua!
This means the dosages required can vary significantly.
500mg of amoxicillin would be a very large overdose for a 2kg Yorkshire Terrier, so whilst the active ingredient in the drug may be the same, we would never recommend using an antibiotic prescribed for a human being on your pet.
How do I give my dog antibiotics?
Antibiotics can be tricky to give to your pet. There are some solutions to administering antibiotics, which may help a ‘reluctant patient’…
- Try to give the pill in the first bite of your pet’s dinner. That reduces the risk of them getting to the end of their meal, and the tablet just being sat at the bottom of the bowl.
- Put the pills in the fridge (if your vet says it's okay) - when food is cold, it is often less flavorful, and any bitter pills will be easier to swallow.
- Add a small amount of butter or cream cheese around the tablet to make it. slippery and harder to spit out. Dog-friendly peanut butter can also work well for dogs.
- Try using pill pockets - tasty, squishy treats with a hole to hide the pill in. You mould the treat around the pill, making it harder for your dog (or cat) to spot and avoid.
- Speak to your vet about the challenge and ask if there is a palatable or liquid version, or if a long-acting injection might be an alternative option.
Do dogs on antibiotics need probiotics?
For many dogs, antibiotics can disrupt the natural balance of their gut. Whilst many dogs can cope without support, for some, gut support using probiotics, prebiotics, or postbiotics will reduce the chance of having an upset tummy while on the medication.
There are various types of gut support, so make sure you know what you are getting:
- Prebiotics: these essentially try to support the healthy bacteria by providing them with nutrients to support them (“feeding the good bacteria”)
- Probiotics: These are bacteria considered to be beneficial to the gut (“replacing the bacteria killed by the antibiotics with good bacteria”).
- Post-biotics: these are things that would usually be produced by the good bacteria that help the gut stay healthier (“mimicking the good bacteria”)
A balance of all three should provide the best possible support for your pet’s tummy whilst they are on antibiotics, but it may not be necessary. They shouldn’t do your pet any harm if used short-term, so whether you use them or not is entirely your choice. Your vet should be able to recommend a product if you need help choosing the one that's right for you and your pet.