The Side Effects of Insulin in Dogs

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Diabetes mellitus develops when your dog's body loses its ability to produce insulin on its own. Insulin therapy, administered through injections underneath your dog's skin, is widely used to help your diabetic dog regulate their blood glucose. As essential as insulin is to a diabetic dog, it carries with it a number of side effects. These side effects are potentially life-threatening and should be reported to a veterinarian immediately.


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Facts about insulin for dogs

Food is broken down by your dog's body into separate organic compounds; glucose is one of these. Glucose, an energy source for movement, growth, and other functions, needs the hormone insulin to transfer from the bloodstream into individual cells. The pancreas produces insulin and in a healthy dog, produces and releases enough insulin to match the amount of glucose in the bloodstream.


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However, when a dog develops diabetes mellitus, their owner must administer insulin to them usually twice a day. These insulin shots for dogs are given as subcutaneous (underneath the skin) injections to maintain the body's proper blood glucose/insulin balance.

Hypoglycemia (low blood sugar) in dogs

Hypoglycemia (low blood sugar) is the most common side effect associated with insulin. It is an extremely serious medical condition that comes on suddenly, requiring immediate attention. Before taking your dog to your veterinarian, it is critical that you immediately feed them approximately 1 tablespoon of a fast-acting glucose, such as corn syrup or honey, first by rubbing a small amount on your dog's gums and then by feeding them by mouth when they regain their swallowing functions. Do not put anything in your dog's mouth while they are actively having a seizure.


An insulin overdose, missed morning meal, or overexertion can trigger low blood sugar. Do not give insulin if your pet skipped a meal and do not give a double dose or extra doses. Symptoms of insulin overdose include hunger, lethargy, and sleepiness in the early stages followed by staggering gait and then twitching, convulsions, coma, and death.


If you think your pet received too much insulin, contact your veterinarian immediately. In order to more easily keep track of the medication schedule, consider assigning just one family member to be on insulin duty. That way, you might more easily avoid the situation of two people accidentally giving a pet their morning or evening injection twice.


Drug interactions from insulin in dogs

It is critical that you inform your veterinarian of all medications your dog is taking so that they can determine whether they will negatively affect your dog's insulin therapy. The following drugs can counter the effects of insulin and should be avoided:



  • Corticosteroids
  • Propranolol
  • Tetracycline
  • Aspirin
  • Epinephrine
  • Furosemide
  • Digoxin
  • Thyroid hormones
  • ACE inhibitors

Allergy and insulin resistance in dogs

The Vetsulin insulin product is manufactured from pork and pork products and should not be given to dogs known to have a pork allergy. Signs of an allergic reaction to Vetsulin include difficulty breathing; hives; and swelling of the lips, tongue, or face.


The makers of Vetsulin explain that porcine insulin and canine insulin are not the same as human insulin. Porcine insulin has the same amino acid sequence as canine insulin. This similarity means it is less likely for dogs to develop anti-insulin antibodies.

Your dog's insulin needs may change, causing blood glucose levels to remain high despite regular insulin therapy. Insulin resistance also results from adverse drug interactions and the presence of infectious agents in the body, especially urinary tract infections. This is also true for certain preexisting medical conditions, such as hypothyroidism, liver and kidney disease, and certain forms of cancer. Cushing's disease, or hyperadrenocorticism, is the most common cause of insulin resistance in dogs.



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