Canine Reactions to Too Much Thyroid Medicine

Some older dogs that are medium to large breeds develop thyroid problems. When a dog is low in thyroid hormone the condition is known as hypothyroidism. Symptoms of hypothyroidism in dogs include hair loss, dull coat, dry skin, weight gain, difficulty with cold weather and a slowed heart rate. The disease occurs because the thyroid hormones are being suppressed. It is diagnosed through blood tests. Treatment is thyroid hormone which comes in a pill form. Once the dog is started on the thyroid medication it must be watched for signs and symptoms of having too much medication. Once the medication is started, it may take a few months to reach an equilibrium of thyroid medication in the dog.

  1. Weight Control Problems

    • While your dog with hypothyroidism may lose weight with the treatment, you must watch for excessive weight loss. Excessive weight loss could mean that your dog is getting too much thyroid medication.

    Feeding

    • Another symptom to watch for is excessive hunger. If you notice that your dog is always hungry but is still losing weight, you must inform your veterinarian so that repeat blood tests can be completed to check the thyroid level.

    Personality Changes

    • Another effect of having an overabundance of thyroid medications is a personality change such as a dog who is normally calm becoming nervous or aggressive around people.

    Heart Rate Changes

    • Another side effect of having too much thyroid medication is a dramatic change in the dog's resting heart rate. If the dog is taking in too much thyroid medication, his heart rate will increase. A normal heart rate in a dog is between 60 and 120 beats per minute.

    Changes in Coat

    • Another change that occurs in dogs with too much thyroid medication is a change in the dog's coat. You may notice that it feels oily.

    Treatment

    • Once you alert the veterinarian that there are changes that suggest hyperthyroidism, the blood tests will be repeated to check for elevated thyroid function. Hyperthyroidism suggests that there is now too much thyroid hormone in the blood. If it is found that your dog's thyroid level is high, the medication will be reduced until it is balanced out and there are no longer negative side effects.