The side effects of antibiotics in dogs

Dogs can't tell you exactly how they're feeling, but when your pet starts taking a new antibiotic or steroid, there may be a change in their appearance or behavior that leaves you wondering if something is wrong. Medications prescribed by your vet should be helping your pup heal, but sometimes they cause uncomfortable and annoying side effects along the way.

We spoke with Dr. Aliya McCullough, Fetch’s Chief Veterinary Officer and Director of Veterinary Affairs, to share what pet parents should know about commonly prescribed antibiotics and steroids for dogs — and what side effects you should look out for.

What do antibiotics treat in dogs?

Even the healthiest dogs will likely have to take antibiotics at some point — they’re commonly prescribed medications. According to Dr. McCullough, antibiotics treat bacterial infections in the skin, respiratory tract, urinary tract, blood and more. 

Different antibiotics come with different potential side effects for dogs. When your vet prescribes a new medication, you should ask them about possible side effects right away so you’re prepared. If your pup does have a negative reaction to any antibiotic, Dr. McCullough recommends contacting your vet as soon as symptoms arise.

Side effects of metronidazole in dogs

Metronidazole is an antibiotic that’s usually prescribed to dogs to treat diarrhea, giardiasis and certain types of bacterial infections, Dr. McCullough explains. Generally, dogs take metronidazole for a short period of time, she adds. 

Side effects of metronidazole in dogs are rare, but some pups experience nausea and vomiting. When the medication is given at a higher dosage and for a longer period of time, Dr. McCullough says that some dogs may show neurological side effects like disorientation, incoordination, head tilting, abnormal eye movements and seizures.

Side effects of cephalexin in dogs

Cephalexin is most commonly used to treat simple skin infections but can treat other bacterial infections, too, Dr. McCullough says. Nausea, vomiting and diarrhea are the most common side effects of cephalexin in dogs.

Side effects of amoxicillin in dogs

Dogs are often prescribed amoxicillin when struggling with a urinary tract, gastrointestinal, skin or bacterial infection or pneumonia, Dr. McCullough explains. Amoxicillin may cause gastrointestinal side effects like nausea, vomiting and diarrhea. To lessen the chance of an upset stomach it’s best to give your dog this medication with a meal. Other, less common, side effects of amoxicillin may include: fever, skin rash or bone marrow suppression.

Side effects of Clavamox in dogs

Veterinarians typically prescribe Clavamox to treat respiratory infections, skin infections, infected bite wounds, dental infections and urinary tract infections in dogs, Dr. McCullough says. Like amoxicillin, the most common side effect of Clavamox in dogs is an upset stomach. Dr. McCullough recommends giving your pup this medication with food to help prevent GI issues.

Side effects of steroids in dogs

‍‍Steroids are another common medication for dogs. Vets will often prescribe steroids for their anti-inflammatory properties. Steroids bring down swelling or treat acute or chronic pain, and they work wonders on itchy dogs. These medications can also suppress the immune system, easing the symptoms of allergies and autoimmune-related illnesses.

The side effects of steroids depend on the dosage, Dr. McCullough says — meaning the stronger the prescription, the more potent the side effects. While your dog is on steroids, watch out for these symptoms:

• Increased appetite and thirst
• More frequent bathroom trips

Always talk to your vet about potential side effects from medications. And keep a close eye on your pet while administering the drug, especially when trying out a new antibiotic or steroid.