Welcome to pharmacology by Lecturio. My name is Pravin Shukle
and I will guide you through respiratory pharmacology. When we talk about drugs used in asthma, we have lots of choices.
We have the bronchodilators such as the beta agonists, the methylxanthines, and the muscarinic antagonists. We also have a choice of a number of anti-inflammatory agents
including release inhibitors, slow anti-inflammatory drugs, antibody based therapies and of course steroids. And finally, we have the new class of drugs
called the leukotriene antagonists. They can be lipooxygenase inhibitors,
or they can be receptor inhibitors. These drug classes represent the entire
armamentarium in asthma. and we’re going to go over each of them in turn. Before we do though, let’s start off with
principles of therapy behind asthma treatment. An inflammed airway has thick airways
and the airway itself is narrow. So, when you take a look at a normal airway down here,
you can see that the walls are not thick, and the walls are wide and open.
When you take a look at a constricted airway, you can see that the walls are still the same thickness,
but the entire diameter of the airway has narrowed resulting in a narrower lumen. When you take a look at an inflammed airway,
even though the walls have not constricted in, the walls themselves are thicker,
so you end up with a narrower airway. And finally, in end stage asthma,
you will have a constricted and inflammed airway which results in a very narrow lumen
and real illness from a clinical point of view. So, inflammed airways, the walls are thick, airway is narrow.
A constricted airway, the walls are “closed in” and the airway is narrow. Now, treatment involves two types of therapy. You can bronchodilate
or you can give anti-inflammatories to reduce thickness, or you can do both.