Bronchodilators: Leukotriene antagonists and methylxanthines

00:00 / 00:00



Bronchodilators: Leukotriene antagonists and methylxanthines

Prerequisite basic sciences

Prerequisite basic sciences


Bronchodilators: Leukotriene antagonists and methylxanthines


0 / 11 complete


Bronchodilators: Leukotriene antagonists and methylxanthines

of complete

External References

First Aid








Theophylline p. 712

cytochrome P-448 and p. 253

therapeutic index of p. 235


In obstructive lung diseases like asthma, individuals suffer from reversible narrowing of the airways, medications like bronchodilators are helpful in keeping the airways open.

Now, based on their mechanism of action, bronchodilators can be broadly divided into four main groups; β2-agonists, muscarinic antagonists, leukotrienes antagonist and methylxanthines.

In this video, we’ll focus on the leukotriene modifying agents and methylxanthines.

So, if we take a look at the lungs, you’ve got the trachea, which branches off into right and left bronchi, and then continues to branch into thousands of bronchioles.

In the bronchioles you’ve got the lumen, the mucosa, which includes the inner lining of epithelial cells, as well as the lamina propria which contains many cells like the type 2 helper T cells, B cells, and mast cells.

Surrounding the lamina propria, there is a layer of smooth muscles and submucosa.

The submucosal layer contains mucus-secreting glands and blood vessels.

Now, the molecular pathway that leads to asthma is actually pretty complex but it is often initiated by an environmental trigger.

Allergens from environmental triggers, like air pollutants or cigarette smoke, are picked up by dendritic cells which present them to a type 2 helper T cell or Th2 cell in the lamina propria. These cells then produce cytokines like IL-4 and IL-5 which causes the inflammatory response.

IL-4 is especially important because it leads to the production of IgE antibodies by B cells, and these antibodies bind to FcεR1 receptors on mast cells to activate them.


  1. "Katzung & Trevor's Pharmacology Examination and Board Review,12th Edition" McGraw-Hill Education / Medical (2018)
  2. "Rang and Dale's Pharmacology" Elsevier (2019)
  3. "Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th Edition" McGraw-Hill Education / Medical (2017)
  4. "Triple therapy (ICS/LABA/LAMA) in COPD: time for a reappraisal" International Journal of Chronic Obstructive Pulmonary Disease (2018)
  5. "Exacerbations of COPD" International Journal of Chronic Obstructive Pulmonary Disease (2016)
  6. "Medication Regimens for Managing Acute Asthma" Respiratory Care (2018)

Copyright © 2023 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.