What's new in the updated asthma guidelines? - Harvard Health
The major focus of the updated guidelines is asthma treatment. Most asthma therapies address two causes of asthma symptoms: airway inflammation and constriction. Airway inflammation in asthma is caused by an overabundant and/or inappropriate immune response. It is usually treated with steroids, which help control airway inflammation or swelling over time.
Nerves in the airways control airway constriction. There are two major types of airway nerves: sympathetic and cholinergic. The sympathetic nerve network, specifically the beta-2 nerve receptors, is the most frequent neural target in asthma treatment. Medications that activate the beta-2 nerve receptors are called beta agonists, and. they are usually given as inhaled medications. Beta-agonists are bronchodilators; they relax muscles in the airways, allowing constricted airways to reopen. There are two basic types of beta agonists used in asthma: medications with rapid onset of action and short duration (SABAs), which are used for immediate symptom relief; and medications with longer duration of action and (usually) delayed onset of action (LABAs), which are used for maintenance therapy.
Previously, asthmatic patients requiring daily maintenance or controller therapy used separate steroid and beta-agonist inhalers to manage airway inflammation and constriction. LABAs are favored for maintenance therapy because of their longer duration of action. But for patients already using a steroid and an LABA for maintenance therapy, using a SABA for breakthrough symptoms meant having a second (if the maintenance treatment used a combination steroid/LABA inhaler) or a third (if separate steroid and LABA inhalers are used for maintenance) rescue inhaler. This approach is cumbersome and disruptive for patients.
The update guides using a new type of inhaler that combines a steroid with an LABA as both a controller and rescue medication. Using one inhaler for both maintenance and rescue therapy is a
more effective approach than one that uses multiple inhalers. First, it is easier to correctly use one inhaler than to take several doses from multiple inhalers. Second, using a combination inhaler for the rescue treatment both gives immediate symptom relief and increases the steroid dose. So, this approach increases the amount of both the anti-constriction and anti-inflammation medications.
However, not all combination inhalers are suitable for this approach. To be used for both maintenance and rescue, the LABA has to have a rapid onset of effect. One LABA, formoterol, has a rapid onset of action, and the guidelines outline which combination therapy is effective as both a controller and rescue therapy, and how to incorporate this into asthma treatment.
Recent evidence has shown that the cholinergic nerves are also important in regulating the size of the airway for asthma. The updated guidelines incorporate these findings to include recommendations about using long-acting anti-cholinergic therapies (LAMAs), such as tiotropium (Spiriva HandiHaler) or umeclidinium (Incruse Ellipta), to treat asthma.
A new treatment approach targets specific inflammatory cells. The most
recent studies in asthma have focused on identifying subsets of asthma patients based on distinct inflammation patterns. These studies have led to new therapies targeting particular types of inflammatory cells and their products. These therapies are very specific and don't work for all asthmatics. And they can sometimes provoke serious, even life-threatening, allergic reactions. The updated guidelines provide general guidance on when this new approach may be incorporated into a patient's asthma management strategy. However, since this area is still new, this edition of the guidelines doesn't give specific recommendations regarding these medications.
The new guidelines also address the safe use of the leukotriene inhibitors, zileuton (Zyflo) and montelukast (Singulair). These are effective asthma therapies but can sometimes cause serious side effects. In particular, montelukast has been associated with depression. The FDA has recently added a warning about this concern to this medication. The guidelines outline how it can be used safely.
Measurements of nitric oxide may be used for asthma diagnosis. The update also guides using new techniques to diagnose asthma. The activity of the cells causing inflammation in the airways of people with asthma results in a byproduct called nitric oxide, which is exhaled as the person breathes. Reliable measurements of exhaled nitric oxide have become widely available, and the new asthma guidelines explain how to incorporate these measurements into asthma diagnosis.