Allergic Asthma: Considerations for Single Inhaler Therapy
Introduction. Asthma is a condition that is characterized by symptoms of cough, wheeze and chest tightness. The diagnosis of asthma can only be confirmed by the demonstration of reversible airflow obstruction on formal breathing tests such as spirometry or methacholine challenge.
Treating asthma represents an ongoing challenge for physicians and patients. Research has shown that patients perceive their asthma to be better controlled than it truly is (97% perceived control versus 47% actual control). Additionally, asthma worsenings are prevalent in most patients regardless of level of control. This may lead to an over reliance of reliever/rescue medication (defined as ≥ 4x/week) in some patients.
Allergic asthma – Picking the right combination product While inhaled corticosteroids (ICS) remain the cornerstone of asthma management, many patients require more than one medication that effectively provides short term relief and long term control of their symptoms. This is often the case in patients with an allergic trigger to their asthma symptoms. These patients require careful consideration at both the outset of management (choosing ICS monotherapy) and subsequent addition of a long acting beta agonist (LABA) in patients who progress to dual therapy. Given that the late phase response of the allergic cascade has a significant effect in these patients, in these patients, single inhaler combination medications represent an excellent (preferred) choice for providing immediate relief of symptoms and longer-term control. Think about it. If a patient is reaching for a short-acting brochodilator (SABA) because they just came into a room filled with cat allergen, the reliever (e.g. salbumatol) will only help to open the airways, it won’t do anything for the impending allergic cascade set in motion from inhaling cat allergen. In this circumstance, it makes much more sense to use an ICS/LABA inhaler provided the LABA has a fast onset of action, such as we see with formoterol.
ICS/LABA products currently available on the Canadian market include Symbicort (Budesonide/formoterol), Advair (Fluticasone proprionate/Salmeterol), Zenhale (momestone furoate/formoterol), and Breo (fluticasone furoate/indacaterol). The rationale for a single maintenance and reliever strategy applies only to ICS/LABA combinations where formoterol is the LABA owing to its significantly faster onset of action than see with salmeterol and indacterol.
Single Maintenance and Reliever Therapy (SMART) provides patients with the ability to combine both relief and maintenance therapy in a single inhaler. In Canada, the only combination ICS/LABA that has been Health Canada approved for both regular maintenance and as needed use is Symbicort. The SMART strategy has been tested using Symbicort® in clinical trials evaluating more than 14000 patients. Results from these studies have demonstrated that Symbicort Maintenance and Reliever Therapy2 reduces exacerbations more effectively than Advair® plus SABA or Symbicort® plus SABA while prolonging time to first severe exacerbation3. More importantly, studies using Symbicort SMART therapy demonstrate lower ICS and oral corticosteroid burden over time when compared with other combination therapies.
In summary, asthma management needs to be tailored to the individual. Treatment choices vary but should be based on both immediate and long-term needs for patients. Choosing a strategy that both makes sense and that has been proven to be effective in clinical trials is a “smart” approach for both patient and provider.