With the single combination inhaler, consider the dosing limits of formoterol. The maximum daily amount of formoterol for adolescents and adults is 54 μg (12 puffs) delivered with the budesonide-formoterol metered dose inhaler. When using SMART as reliever therapy, the low-dose ICS-formoterol recommendation remains. However, depending on insurance coverage, a 1-month supply of ICS-formoterol may not be sufficient for additional reliever therapy use.
The role of LAMAs as add-on therapy
Bronchiolar smooth muscle tone is mediated by complex mechanisms that include cholinergic stimulation at muscarinic (M3) receptors.17 LAMAs, a mainstay in the management of chronic obstructive pulmonary disease (COPD), are likely to be effective in reducing asthma exacerbations and the need for oral steroids. When patients have not achieved control at step 4 of asthma therapy, both the 2020 Focused Updates and GINA now recommend considering a LAMA (eg, tiotropium) as add-on therapy for patients > 12 years of age already taking medium-dose ICS-LABA for modest improvements in lung function and reductions in severe exacerbations. GINA recommendations also now include a LAMA as add-on treatment for those ages 6 to 11 years, as some evidence supports the use in school-aged children.18 It is important to note that LAMAs should not replace a LABA for treatment, as the ICS-LABA combination is likely more effective than ICS-LAMA.
Addressing asthma-COPD overlap
Asthma and COPD are frequently and frustratingly intertwined without clear demarcation. This tends to occur as patients age and chronic lung changes appear from longstanding asthma. However, it is important to distinguish between these conditions, because there are clearly delineated treatments for each that can improve outcomes.
The priority in addressing asthma-COPD overlap (ACO) is to evaluate symptoms and determine if asthma or COPD is predominant.19 This includes establishing patient age at which symptoms began, variation and triggers of symptoms, and history of exposures to smoke/environmental respiratory toxins. Age 40 years is often used as the tipping point at which symptom onset favors a diagnosis of COPD. Serial spirometry may also be used to evaluate lung function over time and persistence of disease. If a firm diagnosis is evasive, consider a referral to a pulmonary specialist for further testing.
Choosing to use an ICS or LAMA depends on which underlying disorder is more likely. While early COPD management includes LAMA + LABA, the addition of an ICS is reserved for more severe disease. High-dose ICSs, particularly fluticasone, should be limited in COPD due to an increased risk for pneumonia. For asthma or ACO, the addition of an ICS is critical and prioritized to reduce airway inflammation and risk for exacerbations and death. While a LAMA is likely useful earlier in ACO, it is not used until step 5 of asthma therapy. Given the complexities of ACO treatment, further research is needed to provide adequate guidance.
CASE
For Ms. S, you would be wise to use an ICS-formoterol combination for as-needed symptom relief. If symptoms were more persistent, you could consider recommending the ICS-formoterol inhaler as SMART therapy, with regular doses taken twice daily and extra doses taken as needed.
CORRESPONDENCE
Tanner Nissly, DO, University of Minnesota School of Medicine, Department of Family Medicine and Community Health, 2426 West Broadway Avenue, Minneapolis, MN 55411; nissl003@umn.edu