How can I reduce the risk of liver damage caused by parasitic medication for a dog with a liver condition? Why are there no alternatives other than pharmaceuticals?

Original Question: I realize how important it is to prevent all possible parasites in both our home and on our pets. What are those of us whose pets have a serious chronic illness supposed to do? Our vets don’t really seem to believe that anything other than the pharmaceutical products will work. How damaging are these products for a compromised liver? Last year I spoke to a very nice gent at Bayer who told me that their products have not been tested on dogs with hepatitis, that is understandable. Have no experiences been recorded? Chronic liver ailments are not rare. Any info at all? - Christa

How can I reduce the risk of liver damage caused by parasitic medication for a dog with a liver condition? Why are there no alternatives other than pharmaceuticals? Apr 26, 2018

Hi Christa,

Thanks for your question. I find it an intriguing and challenging one to answer.

I can understand your frustration. One of the problems is that it is very expensive to perform a research trial on a medication to have it approved for use. It takes years and millions of dollars in most cases. A lot of these trials are looking at the effect of the medication on the average healthy dog. In order to understand a drug’s effect and safety issues in a patient with a particular ailment would mean that these research trials would have to be performed on a huge array of patients with varying disease conditions. It’s just not realistic. So, unfortunately, it would be difficult to impossible to find the effect of a drug on a patient with an individual disease and have sufficient data to confirm it. However, in the general research trials, they do report the negative effects that are experienced by the various systems in the body. So good medical sense is applied to these cases. For example, if a drug is known to create an issue with the liver, either causing it in the occasional patient to become inflamed, cirrhotic, reactive etc., then you would really consider the benefits of that drug and weigh it against the risk of a potential reaction in a patient that already has a liver condition.

Let’s keep in mind that the category of drugs that you are mentioning, namely anti-parasitic drugs, are largely used to prevent a condition and for this purpose, they are an elective, or unnecessary, treatment. They will reduce or eliminate the risk of contracting these particular parasites, but they are still optional. Furthermore, a lot of parasitic infections are easily treated even if your dog became infected with one of these. So contracting entities like fleas, roundworm, hookworm, coccidia, and ear mites, for example, are all conditions that can be easily treated after the fact. The 2 conditions that we use these drugs to prevent that are of greater concern, with a more significant possibility of negatively impacting your pet’s health, and that are much more difficult to successfully treat, are heartworm contracted from mosquitoes and Lyme disease contracted from ticks. These are the conditions we particularly try and prevent with these medications.

So here is my advice for your particular situation. I would speak to your veterinarian about the risk of these conditions in the area where you reside. I would investigate how that risk can be reduced without first having to administer a medication. For example, the risk of being exposed to ticks and contracting Lyme disease can be reduced by avoiding wooded areas, tall grass, walking along defined paths rather than through fields, using protective clothing, and checking your dog daily for ticks and removing them before they can transmit Lyme. If you and your veterinarian want to further reduce the risk, then these medications can be used. In that case, I would strongly recommend using good medical principles to ensure that your pet is not experiencing a negative effect. You would do this by getting baseline values from hepatic testing, beginning the treatment and then monitoring the response both clinically and by repeating those same tests to track the reaction in the liver to those drugs. You could also administer supplements meant to protect the liver against damage, which may already be doing.

As for the other issue about using a different product that is all natural and safe, versus a medication that needs to be metabolized more significantly by the body, it all depends on what the product is and its effectiveness. Veterinarians are not well educated in alternative therapies and naturopathic products. This is not a part of the regular curriculum for traditional veterinary degrees. You will, however, find veterinarians who have taken an interest in this category of medicine and received further training or certification in it. My recommendation is that you find such a veterinarian and seek a second opinion.

Thanks for your question. It was a good one.

Dr. Clayton Greenway

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