It’s pretty common when you take your dog or cat to the vets, to come away with some prescription medication for your pet. It can sometimes be overwhelming trying to take in all the information that is given to you during the consultation with your vet. And you can be left feeling like you more or less have the gist of things. But aren’t quite sure what each medication does exactly. There are a huge number of different medications that we use in animals. And each is often available from more than one pharmaceutical brand. Resulting in it having a number of different trade names, just to confuse things further! One of the commonly administered types of drugs is the antibiotic. Antibiotics are then split into different types depending on their chemical structure and how they act. In this article, we’re looking at an unusual drug called doxycycline.

What is doxycycline?

Doxycycline belongs to what we call the tetracycline antibiotics, all related because of their chemical structure. It is a broad-spectrum antibiotic, meaning that it can be effective against a range of different bacteria. It is also effective against some protozoan parasites, which are curious, one-celled parasites. Doxycycline is a bacteriostatic antibiotic, so it doesn’t kill bacteria directly. But it stops them from being able to replicate and thrive. Doxycycline, therefore, is a very useful antibiotic to have in our repertoire of veterinary medications.

Why might your pet be prescribed doxycycline?

We often prescribe doxycycline for respiratory (breathing) tract infections; where it is likely that the bacteria susceptible to this antibiotic are the cause of a pet’s infection. This is known as empirical therapy and it is often the case for cats that have upper respiratory infections caused by the well known ‘cat flu‘ (where there is often a bacterial and viral component to the disease) as well as in dogs with more severe kennel cough, rhinitis and sometimes pneumonia, amongst others. 

In addition, doxycycline is the treatment of choice for dogs that have been diagnosed with vector-borne infections (such as Ehrlichia). And as part of the treatment of heartworm disease (which thankfully we don’t see in the UK apart from in imported dogs), in these situations, it is often given for one whole month. 

What is a culture?

Other situations in which we might choose doxycycline include where we have done a test known as culture and sensitivity testing. What this means is that we have taken a sample of infected material and sent it to the laboratory to see if what bacteria grow from it. The identified bacteria then undergoes antimicrobial sensitivity testing. This is where we put different antibiotics to the test to see how effective each one is at fighting the bacteria. This allows the laboratory to send us a report telling us what bacteria are present. As well as the effectiveness of different antibiotics in targeting the bacteria. 

Are there any precautions that should be taken for pets prescribed doxycycline?

Generally, we don’t prescribe doxycycline for pregnant animals or immature ones (this can cause side effects like staining of the teeth). The same goes for pets that have been vomiting or are having trouble swallowing. This is because the possible side-effects of doxycycline include oesophagitis (inflammation of the oesophagus, sometimes with ulceration) and vomiting. It is also for this reason that we would normally advise to give the medication inside some food. This is to help minimise the contact of the drug with the oesophagus. Therefore reduce the likelihood of this occurring. 

It’s important to realise that there are possible side-effects that can occur with all medications, and to follow your vet’s recommendations for safe administration of any drug to your pet. However, it is also important to realise that the medications we use in pet have undergone rigorous testing for safety and effectiveness. This testing also allows us to become aware of any unwanted effects that might be seen, and the likelihood of them. That said, it’s important not to be unduly concerned about these possible side-effects. It certainly doesn’t mean your pet will develop them. As in humans, normally only a small proportion of unlucky pets will suffer unwanted effects from their medication.   

You might also be interested in: