Tylosin, also prescribed under the names Tylan and Tylocine, is a macrolide antibiotic. Macrolide antibiotics are bacteriostatic medications, which means that they do not kill bacteria. Rather, they prevent already-present infective agents from reproducing and wreaking further havoc. With this inhibitive respite, an animal’s native immune system has time to catch up and work naturally against infection.
This antibiotic is typically given to livestock as a feed additive. Among farm animals such as pigs and cows, tylosin is added to water or food in order to promote physical growth and to stem the spread of devastating infectious diseases like diphtheria, pneumonia, and foot rot. In poultry — chickens and turkeys, primarily — it is administered to treat respiratory infections. It is even used in bee husbandry to prevent hive loss due to bacteria.
Make no mistake, tylosin is a very powerful antibiotic, and it is not FDA approved for use in domestic pets like dogs and cats. Even in commercial livestock, particularly those animals raised for food, there are specific cautions and waiting periods that must be followed between taking the drug and being prepared for slaughter. As is the case, however, with a wide range of non-canine-specific medications, veterinary professionals have found this medication can provide off-label benefits to companion animals like dogs when used judiciously.
Depending on the circumstances, tylosin is available in a variety of dosages and formats, including Tylan powder, as a liquid which is administered orally, and by injection. For use in dogs, vets take the whole animal into consideration before prescribing tylosin in any form. Age, weight, and general health all make a difference, as do any other medications a dog is already on, including heart medications and other antibiotics that can mitigate tylosin’s effectiveness.
Having been used for the last few decades to treat respiratory and digestive infectious diseases in farm animals, tylosin has recently started finding favor among veterinarians for related dog health problems. For the most part, tylosin is prescribed for severe and ongoing issues with dog digestive systems that are not responding to other medications, treatments, or therapies. These include:
And, as is also the case for other off-label medications, it has also found favor in the last decade for treating far less serious, typically cosmetic issues. Particularly among Maltese dogs and other white-coated dogs with excessive tear production, tylosin may be recommended to limit tear-staining, a condition called:
You’ll notice that none of these health problems are linked to tylosin’s antibiotic origins, since none are necessarily caused by infectious bacterial agents. For digestive disorders like colitis and inflammatory bowel disease, tylosin is prescribed largely for its anti-inflammatory properties. The drug can offer a dog’s overworked and swollen digestive tract, particularly the large intestine, a period of relief and recovery.
Where exocrine pancreatic insufficiency (EPI) in dogs is concerned, of course, bacterial infections can arise as a secondary issue. EPI itself may be caused either by atrophy or swelling, shrinking or inflammation of the pancreas. In both cases, the pancreas fails to produce much-needed digestive enzymes.
One major symptom of colitis, inflammatory bowel disease, and EPI in dogs is chronic or recurring diarrhea. For dogs who have proven unresponsive to other treatments, or for whom a diagnosis has been made but no true underlying cause has been isolated, tylosin may be an effective treatment option. One problem with it in scientific research — and it’s a big one — is in the subheading.
Tylosin-responsive diarrhea means that while the dog is taking the medication, extreme digestive upset stops relatively quickly, within just a few days, but it is still unknown what that mechanism of action is. In dogs suffering from chronic diarrhea, it is also troubling that the upset returns within weeks of coming off the medication. While it can provide relief, antibiotics are especially risky to health when used long-term.
For this reason, it’s strange and unusual to find that tylosin is prescribed for purely cosmetic reasons to resolve excessive tear production in white-coated dogs such as the Maltese. Tear stains in dogs are a health-related issue, but there are a range of ways, including dietary adjustments, that should be tried before turning to antibiotics.
The side effects of tylosin in dogs can be just as problematic as the health issues it is prescribed to treat. Long-term use of antibiotics, particularly if used for off-label treatments, can put a dog at risk for resistance to other antibiotic medications that may be necessary later on to treat other serious diseases.
As tylosin for dogs is prescribed by veterinarians to provide relief from chronic diarrhea, it is also well worth noting that one major side effect of tylosin is chronic diarrhea. Yes, it can cause or worsen the very problem it is intended to treat. This is one reason why tylosin can only be given to dogs by prescription and under veterinary supervision.
Add to this that tylosin can interact poorly with other antibiotics a dog is taking, and that some dogs are allergic to the antibiotic in the first place, and there’s every chance for a dog’s health to deteriorate further unless great care is taken.
Negative reactions in dogs can happen regardless of the format or dosage. When tylosin is administered as an injection, some dogs experience pain, irritation, and swelling at the site of the injection. In its oral forms, tylosin is notorious for its bad taste, leading dogs to reject or refuse it as a food additive.
Since tylosin’s use as a prescription medication for dogs is still a relatively recent phenomenon, it should only be recommended when other options and alternatives have been exhausted. A study done in Finland, published in 2011, clearly states that tylosin’s mechanisms of action are by no means fully understood, its potential long-term effects are unknown, and its successes are anecdotal rather than scientific.