It is crucial to realize that the underlying problem in an asthmatic's airway is inflammation, which is responsible for the constriction of the airway. To resolve this inflammation, corticosteroid medications have been the cornerstone of therapy, and can be given orally, by injection, or via an inhaler. Usually treatment is started with either an oral corticosteroid (such as prednisone) or a long-acting injection (such as DepoMedrol). These medications are relatively inexpensive and a good response to them helps to confirm the diagnosis.
If the response to oral corticosteroids is good, they may be continued long term, supplemented with some of the other medications mentioned below, or used only during asthma flare ups. Long-term corticosteroid use has some potential for side effects, and feline patients tend to be resistant to these problems. If giving your pet pills is too difficult, especially in a cat who is stressed and having trouble breathing, a long-acting corticosteroid injection can be used periodically to control symptoms. However, cats are more sensitive to potential side effects from these injections, as they are much stronger than the pills. Therefore, injections can only be given periodically without risking the development of diabetes mellitus. If the cat seems to require an injection more frequently than every other month, an inhaler should be considered (see below for details).
When using oral corticosteroids, it is important to taper the dose over time so as to find the minimum dose needed to control symptoms. If higher doses are indefinitely used, the symptoms may become resistant to steroids. This is more of a problem with the injectable steroids and manifests as a shorter and shorter interval between the need for the injection. Again, if this is seen, consider changing to an inhaled form of medication.
Other medications that might be helpful include:
Airway Dilators: Terbutaline (Brethine®) and theophylline are airway dilators commonly used in the management of asthma. It makes sense that if constriction is an important feature of this disease that eliminating constriction would be therapeutically helpful. Terbutaline is available orally or as an injectable. Some veterinarians encourage owners to keep a bottle of injectable terbutaline at home in case of a crisis and show them how to give it. If you are interested in this, let your veterinarian know. Theophylline is an oral medication usually given once a day at bedtime.
Cyproheptadine: One of the biochemicals involved in the asthma inflammation cascade is called serotonin. It is directly involved in the airway constriction of cats. Cyproheptadine is an anti-serotonin medication with concurrent antihistamine properties. It is often used in cats who need extra help beyond their steroids or who are having problems that preclude steroid use. Side effects of cyproheptadine include increased appetite and sometimes tranquilization. Many cats are able to have their asthma managed with this medication alone and no corticosteroids at all.
Minimizing irritants in the air is always helpful to an asthmatic cat, therefore:
- Do not allow cigarette smoke in the cat’s environment.
- Use dustless cat litter.
- Consider non-topical insecticides. (And no sprays, either.)
- Regularly replace air filters at home.
It is important to realize asthma can progress to a respiratory crisis that can become a life-threatening emergency if ignored. If your cat begins to breathe with an open mouth or if you see excessive abdominal movement during respiration and the cat is not purring, you may have an emergency situation. If this occurs, you should contact your veterinarian immediately.
Human asthmatics have enjoyed the benefits of portable inhalers for years. These handy devices deliver medication locally to the airways, thus minimizing drug side effects to the rest of the body while maximizing the desired response. With cats, a spacer needs to be used with an inhaler. This tubular chamber is attached to the inhaler on one end and a face mask on the other. The inhaler is actuated into the spacer and the cat simply breathes in the spacer’s contents for seven to 10 breaths. Corticosteroid inhalers, of which Flovent® is the most popular, are typically used twice daily long term, while airway dilator inhalers such as albuterol-containing Proventil® or Ventolin® are used for flare ups.
The Aerokat device (www.aerokat.com) comes with the spacer and an appropriately-sized face mask. Your veterinarian will need to prescribe the inhaler from a regular human pharmacy.
Cats are generally started on a combination of oral prednisone and the inhaler and gradually maintained on only the inhaler.
Whenever your pet is showing signs of a health issue, your first step is to contact your primary care veterinarian. If it is indicated that your cat may suffer from asthma or other serious condition, a veterinary specialist is available at an ExpertVet certified or affiliated hospital.