Asthma is a lifelong condition that involves narrowing, swelling, and inflammation of the airways. It has no cure; however, inhaled medications can be used to manage and control symptoms.
Asthma management typically involves a daily maintenance inhaler and a rescue inhaler (containing rapid action medications) to be used when asthma symptoms arise suddenly. Maintenance inhalers typically comprise inhaled corticosteroids (ICS), such as fluticasone and budesonide. They are also referred to as “controllers” since they prevent or control commonly observed symptoms of asthma. They usually work for 12 to 24 hours. Rescue drugs or inhalers work swiftly and are used only on sudden development of asthma symptoms.
Bronchodilators relaxes bronchial musculature and can be either short-acting or long-acting and include theophylline and muscarinic antagonists. Long-acting β-agonists (LABAs) are controller medications usually combined with an ICS and keep the airways open for 12 to 24 hours whereas short-acting beta (β)-agonists (SABA) are quick-relief medications and keep the airways open for four to six hours only.
SMART inhalers for asthma
In December 2020, the National Heart, Lung, and Blood Institute (NHLBI) updated its guidelines on managing asthma and recommended the use Single Maintenance and Reliever Therapy (SMART) inhalers for asthmatics. The National Asthma Education and Prevention Program and the Global Initiative for Asthma also recommend SMART for moderate to severe asthmatics.
SMART therapy involves the use of only one inhaler for rescue and prevention and comprises a combination of an ICS and a LABA. The ICS drug decreases swelling and mucous production in the lungs, and the LABA prevents bronchial musculature from tightening and works immediately to open the airways. The existing guidelines recommend the combination of budesonide/formoterol (Symbicort) for SMART.
The inhalers have an additional feature: an electronic monitor attaches to the device which automatically tracks the place and timing of use of the SMART medication. Bluetooth sends this data to a mobile app. The app dashboard can be viewed by the doctor (and the patient) and hence understand when symptoms are occurring and how regularly medications are taken. Therefore, the devices are known as smart inhalers.
SMART therapy is recommended for individuals aged above six years with persistent asthma moderate to severe in intensity, and for individuals with a history of asthma exacerbations. On the contrary, individuals who are effectively managing their asthma and do not experience side effects and asthma exacerbations, and do not have risk factors for exacerbations do not need SMART therapy.
Individuals with moderate to severe asthma should take one to two SMART inhalations twice daily if using it for maintenance and as needed to manage sudden asthma symptoms. A maximum of 12 puffs can be taken per day.
A 2018 review of studies found that asthma attacks were lesser among individuals on SMART therapy compared to those receiving conventional asthma treatments. A 2021 review of studies also found that healthcare professionals prefer SMART therapy for decreasing the risk of severe asthma exacerbations in moderate to severe asthma cases.
A 2021 study on the health and economic consequences of SMART use found that it is more cost-effective compared to fixed-dose ICS and fixed combination medications. Further, the Food and Drug Administration (FDA) recently approved a generic version of Symbicort which costs about half the price.
Common side effects associated with Symbicort include
- throat irritation,
- thrush in the mouth or throat (oral candidiasis),
- upper respiratory tract infection.
Potential side effects from inhaled steroids include a hoarse voice, sore throat, oral thrush, cough, and nosebleeds. However, the side effects are less common in low-dose inhaled corticosteroids. SMART may reduce the risk of side effects by lowering the dose of ICS.
Formoterol may cause the following side effects: nausea and vomiting, nervousness, diarrhea, uncontrollable shaking, headaches, muscle cramps, extreme tiredness, dry mouth, sore throat, runny nose, dizziness, and sleeping difficulties.
Other treatment options for the management of asthma
Besides controller and rescue inhalers, there are several other medications and therapies available for asthma which as follows:
- Biologics: They are usually prescribed to individuals with moderate to severe asthma as infusions or injections. These target a particular cell or protein in the immune system to prevent airway inflammation.
- Cromolyn sodium: This drug is a mast cell stabilizer that prevents the release of leukotrienes and histamines from mast cells.
- Leukotriene modifiers (e.g., Montelukast) Leukotrienes are chemicals released by the body that causes symptoms such as breathing difficulties, tightness of muscles, ccoughing, ,and excessive mucous production. These drugs are used for long-term control and they inhibit the production of or effect of leukotrienes.
Digital devices could aid in diagnosing and treating hard-to-control asthma, and potentially decrease the requirements of biological therapies and oral steroids. SMART therapy enables tracking and therefore, daily monitoring of asthma, which would lead to improved clinical outcomes.