Medically Reviewed by Taylor Froiland, PharmD, RPh
Written by Adam McCown, PharmD
As a pet owner, we like to know what is going on with our dogs or cats or other animals. We rely heavily on veterinarians, as we do doctors, but it is still a good idea to have some basic knowledge of what is healthy for our pet and what isn’t. It is also important to know what common diseases and health issues for them are and how to avoid them.
It’s often during this process of informing ourselves about our pet’s health that we discover how similar they are to us. Especially when we are talking about mammals like dogs and cats. Just like us, they’ve got cardiovascular systems, respiratory systems, can come down with colds, catch infections, have chronic joint pain, need antibiotics, you name it. And most of the time, we actually end up consuming similar medications that are only a bit better suited for either an animal or for us.
Respiratory Problems in Dogs
Today’s article is about theophylline for dogs. Theophylline is part of a group of drugs called xanthine bronchodilators. Other related drugs include theobromine and caffeine. These drugs have a number of pharmacologic effects including relaxation of bronchial smooth muscle, bronchial anti-inflammatory actions, central nervous system stimulation, mild diuresis, increased gastric acid secretion and mild cardiac stimulation.
Like many other body systems and functions, your dog’s respiratory system works and looks a lot like our own. It consists of the large and small airways and the lungs. When a dog breathes air in through its nose or mouth, the air travels down the trachea, which divides into the tubes known as the right and left bronchi, then into the smaller airways called bronchioles in the lungs. The bronchioles end in the small sacs called alveoli, where the barrier between the air and the blood is a thin membrane.
Dogs can also suffer from many respiratory problems, just like humans can. These range from bronchitis to pulmonary disorders to asthma. Not to mention airway constriction and inflammation as the result of an allergic reaction your dog may suffer. Dogs can also fall victim to longer term or chronic respiratory diseases like Chronic Obstructive Pulmonary Disease (COPD), a slow, progressive, largely irreversible inflammatory condition that affects the pulmonary or respiratory system.
Theophylline for Dogs with Respiratory Problems
Theophylline for dogs is a bronchodilator that is often prescribed by veterinarians to help relax the muscles in a patient’s lungs and chest so they can breathe easier. It is commonly used to treat a wide range of pulmonary disorders, such as pulmonary edema, bronchial asthma, and the above mentioned chronic obstructive pulmonary disease. In rarer cases, its mild cardiac stimulation properties allow it to be utilized as a treatment for canine heart failure.
Theophylline works by relaxing the muscles in and around the windpipe, thereby dealing with the breathing complications due to asthma or other respiratory problems. The medication effectively works as an airway dilator by widening bronchitis tubes to facilitate easy breathing.
Like all anti-inflammatories, theophylline works largely by targeting your dog’s nervous system in order to affect their body’s immune responses to perceived problems. Swelling, pain, and other symptoms are often the result of the body reacting and responding issues, rather than from the issues themselves. Unfortunately, our dog’s bodies, as well as our own bodies, will sometimes react too strongly, leading to detrimental health effects.
Theophylline’s anti-inflammatory properties rein in your dog’s body’s overreaction, thereby reducing swelling. In this case, it works to reduce the swelling of throat, neck, and chest muscles, allowing your dog to breathe normally.
Side Effects of Theophylline for Dogs
Theophylline is safe and typically well tolerated by both dogs and cats when it is administered under the guidance of a veterinarian. However, it is still possible that your dog could experience side effects with this drug. These potential side effects might include:
- Central nervous system stimulation
- Gastrointestinal upset, including nausea and vomiting
- Heart palpitations
In most cases, the side effects of theophylline can be managed by adjusting the dosage given to your dog. Other times, the prescribing veterinarian will begin your dog on a lower dose and then work up to a higher dose once they see that the drug is well received. In any case, you should not change the dosage given to your pet without the consent of your vet or without them instructing you to do so.
If your dog experiences prolonged vomiting or diarrhea, however, or he or she develops hives or other signs of an allergic reaction, then they should be taken to the veterinarian as soon as possible.
Drug Interactions of Theophylline
Due to the way in which theophylline is absorbed into your dog’s body, there are a number of drug interactions that you have to watch out for. Theophylline is metabolized by cytochrome P-450 enzymes of the liver, so other drugs that are metabolized by this enzyme system may interact with theophylline in unexpected or negative ways.
For example, drugs that inhibit the metabolism of and increase levels of theophylline include: allopurinol, beta-blockers, propanolol, cimetidine, calcium channel blockers, corticosteroids, thiabendazole, exogenous thyroid hormone, macrolide antibiotics, and flouroquinolone antibiotics. Drugs that may increase the metabolism of and decrease levels of theophylline include: barbiturates, rifampin, carbamazine, charcoal, phenytoin, ketoconazole, and beta-agonists.
Theophylline is typically well received by dogs, however certain patients should avoid this medication. First off, pregnant or nursing pets should not consume theophylline. You should also use with caution in patients with severe heart disease, cardiac arrhythmias, GI ulcers, hyperthyroid, glaucoma, high blood pressure, or with a history of seizures, liver, or kidney disease. Do not give theophylline to your dog if they have had an allergic reaction to theophylline, ethylenediamine, or xanthines.
Theophylline can help your dog breathe easier and overcome even their severe respiratory problems. If you think that theophylline might be right for your pet, talk to your veterinarian professional today about a prescription.