How Does Albuterol Work?
Autonomic Nervous System (ANS)
This is your bodily system that contains all your nerves. It also contains neurotransmitters. Your brain controls this system. Simply put, it allows your brain to make changes inside your body based on your environment.
It has two parts.
- Sympathetic Nervous System (SNS) This system opens airways. Albuterol acts on this system to open airways. I will discuss how it works in this post, so bear with me.
- Parasympathetic Nervous System (PNS) This system constricts airways. Muscarinic medicines like Atrovent block this effect to open airways. I will describe this in detail in my next post. I will describe how muscarinics work in my next post.
Sympathetic Nervous System (SNS)
It allows your body to respond to stress. It prepares you to either fight or run away. So, it’s often referred to as the “Fight or Fright” system. So, how does this affect COPD. Well, allow me to explain.
Imagine you are walking through the woods and see a bear. That bear is standing with it’s teeth gnarling. Saliva is dripping from it’s jaws. It’s paws are sharp and shiny. Almost instantly, your heart rate increases. Your breathing becomes easy. Your thinking becomes clear. You know exactly what to do.
This all happens because your fright triggered your brain to use this system. It’s useful because it prepares you to respond to danger. And, a part of this response is to open airways. This allows you to breathe easy. It allows you to think clearly. And physicians use medicine to mimic this response.
So, what happens?
SNS receptors are attached to blood vessels, heart muscle, and airway walls.
- Alpha 1 (A1) Receptors They line heart muscles. When stimulated, they cause your heart rate and rhythm to increase. This assures your major organs receive plenty of oxygen to operate clearly. An old medicine called epinephrine attaches to these receptors. So, epinephrine makes your heart beat faster and stronger. Albuterol barely effects these receptors if at all. So, it has a very negligible effect on your heart.
- Beta 1 (B1) Receptors They line blood vessels and heart muscle. They cause your blood vessels to constrict. This increases your blood pressure. It increases the flow of blood to vital organs, like your brain, heart, and lungs. Epinephrine attaches to these receptors to increase your blood pressure. Albuterol barely effects these receptors if at all. This also helps to make side effects negligible.
- Beta-2 (B2) Receptors They line airway walls. When stimulated, they send signals to airway smooth muscles telling them to relax. When they relax, airways open up. Medicines that are attracted to B2 Receptors are called beta adrenergics. Epinephrine is a strong B2 adrenergic. But, it was not ideal due to it’s strong affinity for A1 and B1 receptors.
This wisdom inspired researchers They yearned to fine tune the epinephrine molecule. They wanted to create a medicine that only stimulated B2 receptors. This is how they created medicines like albuterol (Ventolin) and levalbuterol (Xopenex). These are medicines that open airways fast with negligible side effects.
Short-Acting Beta Adrenergics (SABAs)
Ventolin lasts 4-6 hours. Xopenex lasts 4-8 hours. They are short acting. They are your rescue medicines.
Long-Acting Beta Adrenergics (LABAs)
These are beta adrenergics that last 12-24 hours. They only need to be taken once or twice daily. They sometimes come by themselves in inhalers like Serevent. But, most often they are just one ingredient in combination inhalers like Advair, Symbicort, Dulera, and Breo.
Today, there are all sorts of beta 2 adrenergic medicines. Albuterol is just one. And now you know how they work. It sometimes is inhaled in combination with a muscarinic called Atrovent in Combivent and Duoneb. Atrovent is a muscarinic. I will describe how that medicine works in my next post. So, stay tuned.
Which of the following best describes your COPD diagnosis?