The Role of Inhaled Corticosteroids in Canine Inflammatory Airway Disease

Sponsored by Trudell Animal Health

Respiratory diseases are common in veterinary medicine and encompass a broad range of conditions along the respiratory tree, including the upper respiratory tract (eg, nose, pharynx, larynx, trachea) and lower respiratory tract (eg, bronchi, lungs). Respiratory tract diseases may be acute or chronic, infectious or noninfectious, and primary or secondary.¹ Inflammation is commonly involved in respiratory tract diseases and is especially important to recognize in chronic conditions that do not have a definitive cure.¹ In such cases, corticosteroids can be helpful in minimizing inflammation, managing clinical signs, and maintaining quality of life.¹ Eosinophilic bronchopneumopathy and chronic bronchitis are common examples of canine respiratory tract diseases that can benefit from the anti-inflammatory effects of corticosteroids.¹

Corticosteroid Therapy

Oral and injectable corticosteroids have historically been heavily relied upon to treat the inflammatory component of many respiratory tract diseases; however, their systemic side effects (eg, polydipsia, polyuria, polyphagia) and associated clinical signs (eg, panting, increased risk for obesity) can be detrimental to patient quality of life, especially with chronic use.¹

An alternative route to oral or injectable corticosteroids is inhalation.¹ Fluticasone propionate is one of the more common inhaled corticosteroids and tends to be preferred over others due to its potency and long half-life.¹

Advantages of Inhalant Corticosteroids

With inhaled corticosteroids, systemic absorption is minimized, which reduces many of the unwanted side effects of corticosteroids.^1-3 Inhaled corticosteroids also have more direct impacts at the site of inflammation, and less of the drug may be necessary to achieve the appropriate effect.² With appropriate training, treatment using inhaled corticosteroids can be easier than administering pills and does not require an office visit for injections. One study showed that >80% of pet owners found using inhaled medication with a veterinary valved holding chamber to be easier than giving pills to a pet with breathing problems.⁴

Inhalant Therapy for Canine Respiratory Disease

Although feline asthma is the hallmark condition for which inhaled corticosteroids are used, inhaled corticosteroids can also be beneficial in canine inflammatory airway disorders.¹ Patients with chronic inflammatory conditions that induce coughing, thereby perpetuating inflammation (eg, chronic bronchitis, eosinophilic bronchopneumopathy), can benefit from the decreased inflammation achieved through direct application of corticosteroids.¹ A study of 13 dogs with chronic bronchitis or eosinophilic bronchopneumopathy showed improved clinical signs and reduced side effects in patients receiving inhaled corticosteroids.² Due to the progressive nature of conditions like chronic bronchitis, it can be speculated that using corticosteroids early in the course of disease provides an opportunity to slow down the disease process. Inhaled corticosteroids may also be useful in cases of noninfectious chronic rhinitis (lymphoplasmacytic rhinitis).^1,5

Transitioning to Inhalant Corticosteroids

Client resistance to using inhalants instead of oral or injectable medications may occur. Common barriers include a poor understanding of how to transition from oral medications to inhalants, perceived difficulty of using inhaler devices, and hesitation for financial reasons; however, the former concerns can be managed with communication and training. For dogs already receiving oral corticosteroids, weaning from oral to inhaled forms requires only a 2-week overlap.⁴

Demonstrating proper technique and choosing a device that is right for the pet and pet owner may alleviate concerns over using an inhalant device. Many resources demonstrating proper technique are available on the internet, or training may take place within the clinic. Choosing the right inhalant device and delivery system likewise facilitates ease of use. In animals, inhaled corticosteroids are typically administered via metered dose inhaler. Coordination of breathing pattern with administration is important for medication delivery; however, this tends to be impractical in animals. Instead, a spacer chamber with a mask can be attached to the metered dose inhaler, allowing the animal to breathe in the medication without having to coordinate their breathing.¹

Cost of inhaled corticosteroids may be a factor for some pet owners; however, ease of delivery, better compliance, and fewer side effects often outweigh the costs for pet owners.⁴

Choosing an Inhalant Delivery System

Conditioning a patient to using an inhalant chamber for inhaled corticosteroid delivery involves patience and positive reinforcement. The dog should be allowed the time to become acclimated to the device itself first before the medication is administered or the mask applied to the face. Videos and instructions for how to begin using the device are available online for veterinary teams and pet owners.

Conclusion

Inhaled corticosteroids can offer tremendous benefits for dogs with chronic inflammatory respiratory diseases. Side effects are minimal as compared with using systemic routes of administration. In many cases, inhaled corticosteroids can be easier to administer than oral medications and are safe for long-term disease control.