What Are Antibiotics for Dogs? And Does My Dog Need an Antibiotic?

When your pup develops a bacterial infection, antibiotics for dogs can be a lifesaver. These medications work by eliminating harmful bacteria, helping your dog feel better and preventing the infection from worsening.

We spoke to veterinarians to get all the details about these bacteria-fighting medications, including how they kill bacteria, the different types, when they’re needed, and how to use them safely.

Antibiotics for dogs are medications designed to combat bacterial infections.

“These infections can affect various parts of the body, such as the skin, respiratory system, urinary tract, or gastrointestinal system,” says Jessica Apted, DVM, regional medical director for Sploot Veterinary Care‘s Denver metro locations.

Antibiotics work by either killing bacteria directly or preventing the bacteria from multiplying, allowing the dog’s immune system to eliminate the remaining bacteria and heal the affected tissues, Dr. Apted explains.

Dog antibiotics come in different formulations to suit your pet’s specific medical needs and other considerations, including your ability to administer the medication on a certain schedule. These include:

• Tablets and capsules: These are the most common formulations, and some antibiotic tablets are even flavored so your dog eats it like a crunchy treat. Not all dogs are fans of swallowing pills or capsules. Hiding tablets and capsules in pill pouches, like Greenies Pill Pockets, can help.
• Liquid antibiotics: Ideal for dogs who struggle with pills, liquid antibiotics can be given into the mouth via syringe.
• Topical treatments: Antibiotic creams, ointments, or sprays are used for skin infections, wounds, or hot spots. Ointments that contain multiple ingredients (antibiotics, anti-inflammatory medication, anti-yeast medications) are commonly used for ear infections.
• Injectable antibiotics: These medications, which are typically administered in a clinic setting by a veterinarian, are often used for severe infections or when oral medications aren’t an option.

Antibiotics for dogs are categorized into different classes, each targeting specific types of bacteria and infections.

Within the classes, there are many antibiotics available. Some of the most commonly prescribed antibiotic medications include:

• Amoxicillin
• Amoxicillin/clavulanate (Clavamox)
• Cephalexin (Rilexine)
• Doxycycline(Doxirobe)
• Enrofloxacin (Baytril)
• Gentamicin
• Metronidazole
• Clindamycin(Clintabs, Antirobe)
• Cefpodoxime(Simplicef, Cefpoderm)
• Marbofloxacin(Zeniquin)

Veterinarians choose an antibiotic based on the infection’s location; the likely bacteria involved; and, when possible, results from a culture and sensitivity test, says Kelly Diehl, DVM, senior director of science communication at Morris Animal Foundation.

The culture and sensitivity test analyzes a sample in a lab from the infected area to identify the bacteria and determine the most effective antibiotic to treat it.

Factors like your dog’s breed, age, weight, medical history, and potential drug sensitivities also play a role in the vet’s decision.

Antibiotics for dogs are used to treat a variety of bacterial infections that can occur in any part of the body.

Vets prescribe antibiotics when they diagnose a bacterial infection that can’t be resolved with conservative or supportive care without medication.

Some infections, like bladder infections, abscesses, or severe wounds, almost always require antibiotics, while other less-complicated infections might resolve with supportive care and a conservative approach.

Some of the most common conditions antibiotics are used to treat:

• Abscess
• Anal gland infections
• Pyoderma (bacterial skin infection)
• Otitis (ear infection, which may be bacterial)
• Oral or dental infection
• Eye infection
• Bladder (lower urinary tract) infection
• Lyme disease and other tick-borne infections
• Pneumonia
• Kennel cough and other upper respiratory infections (which may be bacterial)
• Diarrhea due to bacterial overgrowth
• Preventive measures, such as after surgery, to reduce the risk of secondary bacterial infections

“Most dogs tolerate antibiotics, but just like some people, they can have reactions,” Dr. Diehl says.

The most common side effects are related to stomach upset:

• Nausea
• Vomiting
• Diarrhea
• Loss of appetite

If these side effects occur, they are usually mild and manageable.

If symptoms are severe or ongoing, contact your vet for advice.

The dosage, timing, and method of administration will depend on the type of antibiotic and its form.

• Oral antibiotics, which come as tablets, capsules, or liquids, should be given with or without food as directed by your vet.
• Topical antibiotics should be applied directly to the affected area as directed by your vet.
• Injectable antibiotics are administered by your vet in a clinic setting.

To keep your dog safe and increase the chance of effective treatment, follow these key safety tips:

• Follow your vet’s instructions. Stick to the prescribed dosage and treatment schedule exactly as directed by your vet.
• Never use leftovers. Don’t give antibiotics prescribed for another pet or person, as they may not be appropriate for your dog’s condition, health, or weight.
• Store medications safely. Keep antibiotics out of reach of pets and children. Some antibiotics require refrigeration, so follow storage guidelines carefully.
• Complete the course. Make sure your dog receives every prescribed dose. Stopping treatment early can result in incomplete recovery, which, in some cases, can be life-threatening. It can also increase the risk of antibiotic resistance, making infections more difficult to treat in the future, says Dr. Diehl.

Giving your dog antibiotics is usually a relatively smooth process, but there are some situations that would warrant a call to your vet. These include:

• Signs of an allergic reaction: Dr. Diehl says allergic reactions to antibiotics in dogs are uncommon, but they can occur. Symptoms like swelling, difficulty breathing, or severe itching require immediate medical attention.
• Persistent side effects: If your dog experiences ongoing vomiting, diarrhea, or loss of appetite that doesn’t improve, give your vet a call.
• Antibiotics seem ineffective: If your dog’s symptoms persist or worsen, or if new symptoms appear, reach out to your vet.
• Missed doses: Contact your vet for guidance on how to proceed if you accidentally miss a dose.
• Accidental overdose: If your dog consumes more antibiotics than prescribed, call your vet, an emergency clinic, or the Pet Poison Helpline at (855) 764-7661 right away.

What antibiotics are safe for dogs?

All antibiotics are generally considered safe for dogs when prescribed by a veterinarian. Side effects are relatively rare, but if you notice unusual symptoms, contact your veterinarian right away.

Can I get antibiotics for my dog without going to the vet?

No, you should never give your dog antibiotics without a prescription from a veterinarian.

Over-the-counter antibiotics for dogs are not available, except for some topical treatments like triple antibiotic ointments—and for good reason. Misusing antibiotics can harm your dog or contribute to antibiotic resistance.

Always consult your vet to ensure your dog gets the right medication and dosage for their specific condition.

Can I give my puppy antibiotics?

Yes, antibiotics can be given to puppies if prescribed by a vet. Dosages for puppy antibiotics are carefully calculated based on their age, weight, and specific health needs, so never give antibiotics without veterinary approval.

What is amoxicillin for dogs used for?

Amoxicillin for dogs is an antibiotic used to treat certain bacterial infections—most commonly skin, respiratory, and urinary tract infections.