Asthma in Pets - Part 2

Asthma is an inflammatory disease affecting the smooth muscle of the bronchi. This month we continue our discussion, beginning with the use of flaxseed oil.

Flaxseed oil is derived from the seeds of the flax plant and has been proposed as a less smelly alternative to fish oil. Flaxseed oil contains alpha-linolenic acid (ALA), an omega-3 that is ultimately converted to EPA and DHA. It contains higher levels of omega-3 fatty acids than fish oil. It also contains omega-6 fatty acids.

Many species of pets (probably including dogs and cats) and some people cannot convert ALA to these other more active non-inflammatory omega-3 fatty acids. In one study in people, flaxseed oil was ineffective in reducing symptoms or raising levels of EPA and DHA. While it has been suggested as a substitute for fish oil, there is little evidence it is as effective when used for the same therapeutic purposes as fish oil.

Therefore, supplementation with EPA and DHA is important, and this is the reason flaxseed oil is not recommended as the sole fatty acid supplement for pets. (It can be used as a coat conditioner.) Some new studies are showing promise with flaxseed oil, so check with your veterinarian.

The essential fatty acids in flax can be damaged by exposure to heat, light, and oxygen (essentially become rancid). For this reason, you shouldn't cook with flaxseed oil. A good product should be sold in an opaque container, and the manufacturing process should keep the temperature under 100 degrees F (some products are prepared by cold extraction methods). Some manufacturers combine the product with vitamin E because it helps prevent rancidity. The best use of flaxseed oil is as a general nutritional supplement to provide essential fatty acids.

It appears to be a safe nutritional supplement when used as recommended.

Orthomolecular Therapy

Orthomolecular medicine, (often called "megavitamin therapy") seeks to use increased levels of vitamins and minerals to help treat a variety of disorders. While daily amounts of vitamins and minerals have been recommended as an attempt to prevent nutritional deficiencies, orthomolecular medicine uses higher doses as part of the therapy for disease.

The pet food industry relies on recommendations by the National Research Council to prevent diseases caused by nutrient deficiencies in the "average" pet, yet the NRC has not attempted to determine the optimum amount of nutrients or their effects in treating medical disorders. While a minimum amount of nutrients may be satisfactory in preventing diseases caused by nutrient deficiencies, it is important to realize that there is no "average" pet, and that every pet has unique nutritional needs.

It is unlikely our current recommendations are adequate to maintain health in every pet. Each pet has unique requirements for nutrients. For example, in times of stress or disease, additional nutrients above and beyond those needed for health will be required. Orthomolecular medicine evaluates the needs of the individual pet and uses increased nutrients to fight disease.

NOTE: Owners should not diagnose and treat their pets without veterinary supervision. Many medical disorders present similar symptoms. And, megavitamin therapy can be toxic if not used properly.

The orthomolecular approach to treating asthma uses a hypoallergenic, healthful diet as the starting point. This diet should be free of chemicals, impurities, and by-products. A blood profile is done to rule out endocrine diseases, as antioxidants may create changes in blood values that are normally used to screen for these disorders.

Treatment requires borrowing from treatments recommended for other allergic or inflammatory conditions and uses vitamin A (10,000 IU for small dogs and cats, up to 30,000 IU for large dogs), crystalline ascorbic acid (750 mg for small dogs and cats, up to 3000 IU for large dogs), and vitamin E (800 IU for small dogs and cats and up to 2400 IU for large dogs). The antioxidant mineral selenium (20 mcg for small dogs and cats, up to 60 mcg for large dogs) is also added to the regimen. Once asymptomatic, a maintenance protocol using lower dosages of vitamins A and E and the mineral selenium is prescribed to reduce the change for toxicity.

Other Natural Treatments

Other complementary therapies for pets with asthma include the herbs: boswellia, cat's claw, coltsfoot, ephedra, feverfew, garlic, German chamomile, Ginkgo biloba, licorice, lobelia and turmeric. Also see the TotalHealth article on Herbs For Pets With Asthma.

Often asthmatic pets still require conventional medications. The supplements can be used in conjunction with conventional therapies, as they are often ineffective by themselves in patients with severe asthma. The natural treatments are widely used with variable success but have not all been thoroughly investigated at this time.

The most natural diet will improve the pet's overall health.

Conventional Therapy

For dogs and cats with asthma, conventional therapy includes the use of corticosteroids and bronchodilators.

Corticosteroids can be given by injection, by mouth, or by both routes. The most commonly used corticosteroids are prednisone, prednisolone, dexamethasone, and triamcinolone. Corticosteroid injections can be short-acting or longer-acting injections.

While very effective when used to control inflammation and decrease airway sensitivity, corticosteroids have both short and long-term side effects. Short-term include; increased water intake, increased urination, increased appetite, destruction of joint cartilage, and very rarely, either depression or excitability. Long-term effects include suppression of the immune system, infections, diabetes, liver disease, osteoporosis, Cushing's disease, and obesity. Side effects, both short and long, are common in dogs, but relatively rare in cats.

When needed, short-term use of fast-acting corticosteroids is preferred. Depot injections, while commonly used in cats, should rarely, if ever be used in dogs. In cats, an occasional depot injection (1 to 3 times a year) is usually not associated with side effects, but when possible, short-acting injections and oral corticosteroids are preferred.

Bronchodilators commonly used to treat arthritis in pets include aminophylline and theophylline. These medications are methylxanthine derivatives that act as respiratory smooth muscle relaxing agents. Biochemically, they work by competing with the enzyme phosphodiesterase, which increase the levels of cyclic AMP, resulting in the release of epinephrine. Increased levels of cyclic AMP may also inhibit two chemicals produced in the body, which contribute to signs seen in asthmatic patients: histamine, and the slow-reacting substance of anaphylaxis (SRS-A). In addition to relaxing respiratory smooth muscles, they also relax the smooth muscles of the blood vessels of the respiratory tract and remove excess fluid from the body via their diuretic actions.

Aminophylline and theophylline should be used cautiously in pets with heart disease, stomach ulcers, hyperthyroidism, kidney disease, liver disease, and high blood pressure. Older pets may be more sensitive to side effects. Preexisting heart arrhythmias may worsen in pets receiving aminophylline or theophylline. Additional side effects include central nervous system stimulation and gastrointestinal stimulation. These medications have a narrow therapeutic index, which means there is a very small difference between the effective dose and the toxic dose.

Pets With Asthma