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Side Effects of Antibiotics in Dogs: What are the Side Effects of Giving Dogs Antibiotics?

Your dog is on antibiotics – it’s ok! Even the healthiest, most doted on dogs may occasionally get sick. That’s why veterinarians report that antibiotics are among the most frequently prescribed drugs. A dog on antibiotics could be recovering from a range of illnesses - from an ear infection to Giardia. In some instances, however, the side effects of antibiotics on your dogs digestive system can include vomiting, loss of appetite, and diarrhea. 

While antibiotics are effective in destroying the bacteria that causes your dog to be sick, they often also destroy the “good” bacteria in your dog’s digestive tract, where the all-important gut microbiome lives. You might not have heard of the gut microbiome before — and it may sound like something out of a movie about little green men — but a balanced gut microbiome is critically important your dog’s overall health and immunity. 

In fact, more than 2,000 years ago, the very wise Greek physician Hippocrates said, “All disease begins in the gut.”  

Let’s dive into what happens when giving our dogs antibiotics… 

The Side Effects of Antibiotics in Dogs 

Antibiotics, also known as antibacterials, do what the name implies: they kill or slow the growth of bad, harmful bacteria. The catch-22, however, is that they also kill the good bacteria, which causes the gut microbiome to enter an unbalanced state. 

When there are not enough “good bacteria”, or probiotics, a dog can experience digestive diseases as well as problems with allergies, metabolic disorders like diabetes, immune function, and even psychological issues like anxiety or depression. 

Some antibiotics are worse than others, says Dr. Carlson. “The cephalosporin family of antibiotics tend to affect the gut more than fluoroquinolones and penicillamines, but all antibiotics play a factor in affecting the gut microbiota. 

The side effects that antibiotics cause, says Dr. Carlson, include the very uncomfortable leaky gut syndrome, diarrhea, vomiting, itching skin, yeast infections, behavioral issues, and more. However, gastrointestinal disorders, such as leaky gut syndrome, are the most common side effects of dogs on antibiotics. 

Understanding Leaky Gut Syndrome in Dogs 

An optimal digestive process is dependent on a balanced coating of bacteria in your dog’s intestines. When the bacterial environment is out of balance with too few good bacteria, this intestinal barrier becomes inflamed and permeable, as a result large, half-digested pieces of food leak into the bloodstream – hence leaky gut syndrome! The liver becomes stressed as it attempts to filter out these particles, and the immune system identifies them as foreign bodies and forms antibodies and allergens.  

Leaky gut syndrome in dogs can have a number of unexpected symptoms, but when brought on by antibiotics, the most common symptom is diarrhea.   

Symptoms of leaky gut in dogs include:   

  • Gas 
  • Bloating 
  • Diarrhea 
  • Vomiting 
  • Abdominal pain 
  • Skin conditions such as dermatitis 
  • Allergic reactions such as ear inflammation and infection 
  • Malnutrition 
  • Poor coat health 
  • Weight loss  
  • Hyperactivity and/or aggression 
  • Joint conditions 
  • Thyroid conditions 
  • Immune system disorders such as IBD (Inflammatory Bowel Disease) 
  • Respiratory conditions such as asthma 

Restoring the Balance of the Gut Microbiome 

When giving dogs antibiotics is necessary, there are a few things we can do to help restore the balance of your dog’s gut microbiome and alleviate any side effects of antibiotics symptoms. 

“Use of proper essential fatty acids like EPA, DHA, Linolenic, linoleic and Arachidonic acid are important for repair of damaged gut lining form antibiotics,” says Dr. Carlson. These are a combination of Omega-3 fatty acids and Omega-6 fatty acids. “Probiotics are also an important for the restoration of proper gut colonies.”  

Essential fatty acids are effective in relieving allergy symptoms and inflammation. Probiotics and prebiotics, the food of probiotics, help restore the balance of the gut microbiome and relieve gastrointestinal issues.  

Probiotic supplements, or fermented food, contain live bacteria and yeasts that are beneficial for the digestive system; they are referred to as “direct-fed microbials” by AAFCO (Association of American Feed Control Officials). In the case of antibiotic destruction of “good bacteria,” probiotics can help replace them and restore the balance of bacteria in the gut microbiome. The job of prebiotics is to nourish the good bacteria that exists in the digestive system and promote their growth. 

Prebiotics have been included in pet food for many years, according to Veterinary Practice News, but probiotics are both heat and moisture sensitive, so they would be destroyed in the dog food manufacturing/cooking process. Probiotics and prebiotics are available in: 

  • Yogurt or kefir containing live cultures 
  • Powder 
  • Capsules 
  • Chews 
  • Freeze-dried  

So don’t stress out about giving dogs antibiotics. Remember to finish the entire dose, and then stock up on gut microbiome-boosting probiotic supplements. Giving your dog both pre- and probiotics will keep a healthy level of “good” bacteria, help restore overall health and immunity, and support the happy tail wagginstate of the dogs we love.