Antibiotics for Dogs

Vets can prescribe antibiotics for dogs to treat a range of infections. In this guide we’ll look at the different types of antibiotics available and what they can treat.

What antibiotics can you give your dog?


Just like humans, dogs can develop bacterial infections which may need treating with a course of antibiotics. Antibiotics kill bacteria by damaging their structure or preventing them from reproducing. Just remember, they don’t work against viral or fungal infections.

Broad-spectrum antibiotics kill off many different types of bacteria, whereas narrow-spectrum antibiotics only kill specific types. Without antibiotics, bacterial infections can lead to complications. Your vet may prescribe antibiotics for your dog to treat:


  • Urine infections
  • Eye infections
  • Vestibular disease
  • Mastitis 
  • Conjunctivitis
  • Skin infections
  • Ear infections


Antibiotics can be administered by:

  • Tablets
  • Liquid
  • Capsules
  • Antibiotic eye drops
  • Antibiotic ear drops
  • Antibiotic ointments
  • Antibiotic creams
  • Injection


Prescription antibiotics

Antibiotics are known as prescription-only medicines, in other words, they must be prescribed by a vet. Your vet will prescribe a course of antibiotics if they think an infection won’t clear up by itself or if it could spread to other animals. Prescription antibiotics include:

Clavamox (amoxicillin-clavulanic acid)

Clavamox is a broad-spectrum antibiotic. It’s often given in tablet form but there is a liquid alternative for puppies.

Your vet may prescribe Clavamox to treat infections caused by Staphylococcus, Streptococcus, and E. coli, as well as:

  • Skin infections caused by allergies
  • Respiratory infections 
  • Ear infections
  • Dental infections
  • Urinary tract infections

Clavamox is usually safe for your dog, but as with all medicines, there can be side effects. The most common are:

  • Diarrhoea
  • Vomiting
  • Allergic reactions
  • Weight loss
  • Change in appetite
  • Change in heart or respiratory rate

Due to limited studies, the safety of clavamox during pregnancy and lactation is uncertain. Always ask your vet before giving any medication to pregnant or lactating dogs.


Flagyl (metronidazole)

Metronidazole is a broad-spectrum antibiotic for dogs which has many uses, including treating:

  • Gastrointestinal tract infections
  • Abscesses
  • Hepatic encephalopathy
  • Peritonitis
  • Dental infections
  • Meningitis
  • Genital tract infections

Metronidazole can cross what’s known as the blood-brain barrier and can treat infections that are within the central nervous system. Side effects are usually quite rare, but they can happen. The most common include:

  • Loss of appetite
  • Diarrhoea
  • Vomiting
  • Drooling
  • Excessive sleeping

Dogs on a high dosage may be at risk of more serious side effects like:

  • Paralysis
  • Rapid heart rate
  • Difficulty breathing

The dosage is determined by your vet based on your dog’s age and weight. It’s important not to give your dog double doses – call your vet for advice if you’ve missed any doses. You shouldn’t give metronidazole to puppies or lactating and pregnant dogs.


Cleocin (clindamycin)


Clindamycin is a broad-spectrum antibiotic used to treat a variety of bacterial infections in dogs, including:

  • Wounds
  • Pyoderma (a skin disorder caused by infection)
  • Abscesses
  • Bone and dental infections
  • Toxoplasmosis (parasitic disease)

It’s available on prescription in liquid, tablet and capsule form. Due to its bitter taste, you’ll need to disguise it in your dog’s food. Use a tasty sausage or piece of cheese to help your dog swallow it. If the pill becomes lodged in the throat it can cause ulcers, so let your dog eat plenty of food after taking the medication to help it travel down. Never give your pet two doses at once or any extra doses. 

The potential side effects of clindamycin include:

  • Gastrointestinal upset
  • Vomiting
  • Diarrhoea
  • Bloody diarrhoea

Certain medications can react to clindamycin, so it is important to tell your vet about any medications your dog is taking. This includes vitamins and supplements.


Keflex (cephalexin)


Cephalexin is a broad-spectrum antibiotic effective against several bacteria. It’s used to treat:

  • Urinary tract infections (UTI)
  • Skin and soft tissue infections, such as hotspots and pyoderma
  • Respiratory tract infections
  • Ear infections


It comes in different forms including capsules, oral tablets or chewable tablets. Depending on the type of infection, your vet may also prescribe liquid cephalexin or give an injection.


Side effects of cephalexin are usually less severe than other medications. The most common include:

  • Vomiting
  • Diarrhoea
  • Panting
  • Rapid breathing
  • Drooling
  • Skin rashes
  • Hyper-excitability

Dogs are given cephalexin with or without food. Your vet may advise giving it to your dog with food as this can help prevent any side effects.


Vibramycin (doxycycline)


Doxycycline is a broad-spectrum antibiotic used to treat bacterial infections caused by microorganisms. It’s usually prescribed for:

  • Respiratory infections
  • Urinary tract infections
  • Infected wounds
  • Blood-borne infections
  • Rocky Mountain spotted fever
  • Lyme disease
  • Ehrlichiosis
  • Leptospirosis
  • Canine Parvovirus

Doxycycline is often used to treat a primary infection or as a precaution against a secondary bacterial infection. This includes canine parvovirus that can leave dogs vulnerable to secondary bacterial infections.

It’s available as a tablet, capsule or liquid. The dosage depends on the age and weight of your dog as well as any underlying conditions. It’s best to give it to your dog with food to reduce the risk of any side effects.

Doxycycline is usually tolerated well by dogs but there are always possible side effects. The most common include:

  • Diarrhoea
  • Vomiting
  • Loss of appetite
  • Weight loss
  • Drowsiness

In rare cases, doxycycline can cause more severe side effects such as jaundice, seizures and bleeding. It can also cause limb deformities in unborn puppies so it’s best avoided for pregnant dogs.


Bactrim (sulfamethoxazole-trimethoprim)

 Bactrim combines the two active ingredients trimethoprim and sulfamethoxazole.

The combination of these antibiotics makes them much more effective. When combined, they have a bactericidal effect – in other words, they cause the death of bacteria. Bactrim is available in tablet and liquid form and can be given with or without food. Treatments usually last for five days but can be longer depending on how severe the infection is.

It's a broad-spectrum antibiotic used to treat a range of infections including:

  • Respiratory infections
  • Digestive infections
  • Dermatological infections
  • Kennel cough
  • Nocardia and Staphylococcus
  • Protozoa
  • Pneumonia
  • Prostate infections

Potential side effects can include:

  • Vomiting
  • Diarrhoea
  • Allergic reactions
  • Decreased appetite
  • Fever
  • Decreased energy level or weakness
  • Increased thirst or urination
  • Difficulty breathing


Over the counter antibiotics

In some cases, you might be able to buy some antibiotics over the counter from pet supply stores or online pharmacies without a prescription. But it’s not recommended, as it can be extremely dangerous to give your dog any medication without seeing a vet first.

Amoxil (amoxicillin)

 Amoxicillin is a commonly prescribed broad-spectrum antibiotic for dogs. It works by stopping the growth of bacteria. It’s used to treat:

  • Skin infections
  • Respiratory infections
  • Urinary tract infections
  • Dental issues
  • Ear infections

It comes in tablet, capsule and liquid forms, with the treatment usually lasting around five to seven days. Make sure you speak to your vet first before giving it to your dog. Whilst it’s usually tolerated well by dogs it can have some side effects, including:

  • Diarrhoea
  • Vomiting
  • Loss of appetite
  • Nausea
  • Erythema
  • Urticaria
  • Anaphylaxis

The cost of amoxicillin depends on the dosage needed for your dog, but it’s usually between £10 and £30.


Garamycin (gentamicin)

 Gentamicin is a broad-spectrum antibiotic available as a topical spray, eye drops and topical ointments for the skin and ear. It’s mostly used to treat:

  • Eye infections
  • Outer ear infections
  • Skin infections

It works by preventing the bacteria from making the essential proteins it needs to survive. Gentamicin shouldn’t be used with certain medical conditions for liver or kidney disease, so speak to your vet before you give it to your dog. 

Gentamicin topical sprays contain corticosteroids which may cause certain side effects including:

  • Increased urination
  • Increased appetite
  • Increased thirst
  • Thinning skin
  • Hair loss
  • Decreased muscle mass

Gentamicin eye drops can cause:

  • Eye burning
  • Irritation
  • Eye redness

Gentamicin ear treatments may cause ear redness. In rare cases, it causes more serious side effects, including:

  • Decreased appetite
  • Gastrointestinal signs such as vomiting and diarrhoea
  • Sudden hearing loss
  • Ear pain
  • Head tilt
  • Walking in circles

The cost of gentamicin depends on the form. As an example, 5g gentamicin eye ointment costs between £20 and £30.


The cost of antibiotics for dogs

Antibiotics prices vary depending on the type of antibiotic and the weight of your dog.

The maximum price that a vet can charge for a prescription is £24.40, but this doesn’t include the cost of the antibiotics themselves. Depending on the type of antibiotic and the size of your dog, the cost will vary. On average, a course of dog antibiotics costs between £10 and £30.

With any antibiotics, it’s important to consult your vet to ensure you’re giving your dog the right medication. Always follow the full course of antibiotics to ensure the infection is properly treated. When followed correctly, antibiotics are usually very effective and affordable.





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