In 2007, The Sopranos was a hit TV show, patterned jeggings were a fashion trend, and the National Institutes of Health–sponsored National Asthma Education and Prevention Program (NAEPP) published the second edition of the Asthma Management Guidelines.
A lot has changed since 2007, including in the area of asthma. The NAEPP recently published the third edition of the Asthma Management Guidelines to address these changes. This update reflects recent advances in our understanding of the disease mechanisms causing asthma, and the current best practices to manage asthma symptoms. As such, the updated guidelines are an important tool, enhancing the ability of physicians and patients to control asthma and minimize the impact of this disease on their lives.
The toll of asthma in the US
Asthma is a chronic lung disease afflicting approximately 5% to 10% of the American population. It is characterized by symptomatic periods of wheezing, chest tightness, and breathlessness alternating with periods of essentially normal breathing. The symptomatic episodes can be extremely debilitating, even life-threatening — every year approximately 3,500 people die from asthma, many of them children. Like many diseases, the impact of asthma is greater among minority and economically disadvantaged patients. There is no cure for asthma, so therapy focuses on preventing and treating symptom flares, called exacerbations.
New asthma guidelines update treatment recommendations
The major focus of the updated guidelines is asthma treatment. Most asthma therapies address two causes of asthma symptoms: airway inflammation and airway 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.
Airway constriction is controlled by nerves in the airways. 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 a 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 provides guidance for using a new type of inhaler that combines a steroid with a 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 also are important in regulating airway size in 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.
New treatment approach targets specific inflammatory cells
The most recent studies in asthma have focused on identifying subsets of asthma patients based on distinct patterns of inflammation. These studies have led to the development of new therapies that specifically target 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 as to 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 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 provides guidance on 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.
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