Aerosol Inhalers
Many bronchodilators are administered with an aerosol inhaler designed for cats. This device is an aerosol canister, equipped with a metered dose indicator and a fitted face mask. It delivers measured doses of medication through the mask. It is the most efficient delivery system for directing medication to the cat's affected lung tissues. Most cats learn to accept breathing treatments through the face mask quickly. The AeroKat Feline Inhaler is the most popular such device in use around the world.
Two types of bronchodilators are available for cats: sympathomimetics (often called revivers because they are used for rapid relief of breathing problems) and xanthines, which are prescribed for long term prevention of problems.
Bronchodilators do not reduce the inflammation in the lungs. This is why it is almost always best to give bronchodilators along with corticosteroid drugs. Research suggests that when bronchodilators are used alone, a quiet progression of asthma and irreversible lung damage may result. This is because the inflammatory process is allowed to continue while symptoms are masked with the bronchodilators.
Sympathomimetics
Albuterol (US Proventil®, US, UK Ventolin®; UK Salbutamol®) is the most widely used sympathomimetic for cats. Albuterol relaxes the muscle tissue surrounding feline airways that can spasm in an asthma attack and cause breathing difficulties. It is administered with an inhaler and may be used up to four times daily or as needed if your cat is already taking inhaled steroids. It can also be used every half hour, for 2 to 4 hours in a crisis. Terbutaline is almost identical to Albuterol, but it is given in oral, injectable and syrup forms. A child's syrup form of Terbutaline called Bricanyl® is also used in the UK and Canada.
Salmeterol is a long acting inhaled bronchodilator and it should not be used in a crisis, since it takes 1-2 hours after dosage to take effect. It lasts 8 to 12 hrs in cats.
Xanthines (Theophyline)
Theophyline (Theo-Dur®, Aminophylline®, Corventil D®) is used for long term prevention of breathing problems. It is an oral medication and it is widely prescribed along with Prednisone because as part of this combination, it increases the anti-inflammatory process where other bronchodilators do not.
Side Effects
Side effects associated with sympathomimetics can include palpitations and trembling, tachycardia and musculoskeletal twitchiness. Disorientation and ‘spacey' behavior in cats have been reported with Albuterol.
Using a bronchodilator can be dangerous for any cat with cardiac disease, so inform your vet of any past cardiac problems or symptoms and rule out any possibility of hidden heart disease before beginning therapy with bronchodilators.