Rethinking asthma therapy, part 1: transdermal delivery of β₂-agonists

Asthma and allergies are closely related conditions affecting millions of people around the world. Current treatment options cover many classes of drugs for both acute and ongoing conditions. β2-agonists, leukotriene modifiers, and corticosteroids represent some of the common types of drugs utilized in asthma management. These medications are often delivered via inhalation, oral, or parenteral methods, but each of these modalities faces challenges due to improper technique with inhalers, lessened oral bioavailability due to first-pass metabolism, and reduced compliance of injectable medicines. Transdermal drug delivery may offer a beneficial route of administration that overcomes these barriers as a painless, self-administered form that bypasses first-pass metabolism and can reduce dosing frequency with longer drug release profiles and reduced fluctuations in plasma drug levels. In this two-part mini-review series we will summarize the current literature on transdermal systems for asthma and allergy therapy. Here in Part 1, we cover β2-agonists and discuss the potential of transdermal systems for these drugs. While the body of work with transdermal β2-agonists for asthma treatment is limited, there is still evidence that transdermal systems for asthma has potential to greatly shift the field of asthma therapeutics.