Pharmacology, part 2: Respiratory Medications - Bronchodilators

by Cathy Parkes April 24, 2020

In this article, we cover respiratory medications that cause bronchodilation including beta-2 adrenergic agonists, xanthines and anticholinergic medications. The Pharmacology Nursing video series follows along with our Pharmacology Flashcards, which are intended to help RN and PN nursing students study for nursing school exams, including the ATI, HESI and NCLEX. 

What is a bronchodilator?

A bronchodilator is a drug that relaxes the bronchial muscle resulting in the expansion of the bronchial air passages.

Beta-2 Adrenergic Agonists

What are beta-2 adrenergic agonists?

Beta-2 adrenergic agonists are a drug class used as treatments for respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). Two common medications that fall into this class are albuterol and salmeterol. They can be used alone or in combination with a glucocorticoid or with an anticholinergic medication such as ipratropium.

How do these medications work?

Beta-2 adrenergic agonists, such as albuterol and salmeterol, help with bronchodilation by binding to the beta-2 receptors in the airway smooth muscle. This relaxes the muscle and opens up the airways, making it easier to breathe.

Quick tip: The best way to remember that beta-2 receptors are in the lungs is that you have two lungs, as opposed to beta-1 receptors, which are on the heart, and you only have one heart.

Albuterol vs. salmeterol

The key difference between albuterol and salmeterol is that albuterol is a short-acting beta-2 adrenergic and is used for acute asthma attacks while salmeterol is long-acting and is used more for the prevention of asthma attacks. 

An easy way to remember the difference between albuterol and salmeterol is that albuterol starts with an A, and acute asthma attacks also start with A. Also, salmeterol sounds like salmon, and eating salmon helps you live a long time. Salmon, long life, salmeterol, long-acting!

What are some common side effects of albuterol and salmeterol?

Common side effects of these medications can include nervousness, tremors, chest pain and heart palpitations.

Glucocorticoid interactions

Some glucocorticoids like prednisone, hydrocortisone, or dexamethasone are used for asthma too. If you are using a beta-2 adrenergic agonist like albuterol or salmeterol along with a glucocorticoid, you should administer the bronchodilator first. So use albuterol first, wait 5 minutes, then use the glucocorticoid. This is important to know, because corticosteroids are used preventatively in this case, while albuterol is immediate-acting. 

The easy way to remember that bronchodilators come before glucocorticoids is that B comes before G in the alphabet!

These corticosteroids are also covered in our Pharmacology Flashcards, and can be found in the Endocrine system section. 

Xanthines

What are xanthines?

Derivatives of xanthine are a group of alkaloids used for their effects as mild stimulants and as bronchodilators to treat asthma and COPD. The key medication that falls within this class that you want to make sure you know is theophylline.

What is theophylline?

Theophylline is a medication used for the long-term control of asthma and COPD. It works by increasing cAMP and ultimately results in bronchodilation. However, it comes with some serious side effects and because of that, it’s not used as much as other medications for asthma and COPD. These major side effects can include seizures and dysrhythmias. For more information on the different types of dysrhythmias, check out our EKG Interpretation video series

  • More side effects of theophylline can include GI upset, headache, and nervousness.

Quick Tip: The best way to remember that theophylline has serious side effects is by its name. The name begins with “theo,” which comes from Greek meaning God. So if you take theophylline, you might end up seeing God sooner rather than later because of those very serious side effects!

Anticholinergic Medications

What are anticholinergic medications?

Anticholinergic medications are drugs that block the action of acetylcholine. Acetylcholine (ACh) is a neurotransmitter that transfers signals between cells, often triggering muscle contractions.. An anticholinergic like ipratropium blocks ACh receptors in the airway smooth muscle, causing bronchodilation. 

Ipratropium is an anticholinergic medication you should definitely know about. 

What is ipratropium?

Ipratropium is an oral inhalation medication used to treat chronic obstructive pulmonary disease (COPD). It can also be used to treat rhinitis (runny nose) and asthma. It can be used alone or in combination with albuterol. When used in combination with albuterol, the medication is called DuoNeb.

What are the side effects of ipratropium?

Because blocking ACh receptors can decrease mucus secretion, anticholinergics are known to be drying. The key side effects of this medication include dry mouth, as well as a bitter taste, and throat or nasal irritation, depending whether you are using an inhaler or an intranasal form of ipratropium.

Key patient teaching for ipratropium

You should advise your patients who are taking ipratropium to increase their fluid intake and suck on candy to combat dry mouth symptoms. DuoNeb, which is the ipratropium-albuterol combination, is contraindicated for patients who have a peanut allergy.

Full Transcript

Alright. In this video, we are going to get into respiratory medications. And specifically, we're going to talk about respiratory medications that cause bronchodilation.

So the first class I'm going to discuss here are beta-2 adrenergic agonists. So if you're following along with cards, I'm on card number one, and the two medications that I'd be familiar with that fall under this class are albuterol and salmeterol.

So these medications can be used for asthma or COPD. They can be used alone or in combination with a glucocorticoid or with an anticholinergic medication such as ipratropium.

The mode of action of beta-2 adrenergic agonists is to bind to the beta-2 receptors in the lungs.

So the way to remember that beta-2 receptors are in the lungs is that you have two lungs, as opposed to beta-1 receptors, which are on the heart, and you only have one heart.

So these medications bind to those beta-2 receptors, and they result in bronchodilation. They help open up the airways.

These medications do carry some common side effects including nervousness, tremors, possible chest pain, and possible palpitations.

There is a key difference between albuterol and salmeterol. Albuterol is a short-acting beta-2 adrenergic agonist. It is used for acute asthma attacks. So, Albuterol starts with the letter A, and acute asthma attacks also all start with the letter A, so that will help you remember that.

Salmeterol is long-acting and it is more for prevention of asthma attacks. So I think about eating salmon. Salmon's supposed to be very healthy and it will help you lead a long life if you incorporate salmon into your diet. So I think about salmon and leading a long life, and that helps me to remember that Salmeterol is long-acting.

If you're using a Beta-2 adrenergic agonist with a glucocorticoid, you want to use the bronchodilator first, so use the Beta-2 adrenergic agonist first, wait 5 minutes and then use the glucocorticoid. That's going to be very important to know. And the way you can remember it is that B comes before G. So bronchodilator first, wait 5 minutes, and then the glucocorticoid.

Moving on to card 2, we're going to talk about xanthines. The key medication that falls within this class is theophylline.

So theophylline can be used for long-term control of asthma or COPD. It works by increasing cAMP, which ultimately results in bronchodilation.

It comes with some very serious side effects, however. So in addition to GI upset, headache, and nervousness, it also carries risk for dysrhythmias as well as seizures. And because of those very serious side effects, this medication is not used as much as other medications for asthma and COPD.

If your patient is going to be on theophylline, they will need to get regular blood draws to really monitor the levels of theophylline in their bloodstream. The therapeutic levels should be somewhere between 10 and 20 micrograms per milliliter. The way I remember this medication is the drug name is theophylline. So the beginning of that is theo. So theo means god or godlike. So if you take theophylline, you might end up seeing God sooner versus later because of those very serious side effects.

Now, we're going to talk about anticholinergic medications that are either inhaled or intranasal. The key medication that I would know that's an anticholinergic in this class is ipratropium.

Ipratropium can be used for COPD. It can be used for rhinitis which is a fancy name for congestion like a runny nose.

It can also be used for asthma, but that is really off-label. It can be used alone or it can be used in combination with albuterol. When used in combination with albuterol, that medication is called DuoNeb. So it works by blocking acetylcholine receptors in the airway's smooth muscle which causes bronchodilation.

Because it's an anticholinergic, it will have drying effects. So the key side effects with this medication include dry mouth, as well as a bitter taste, and throat or nasal irritation, depending whether we're using an inhaler or an intranasal form of ipratropium.

So some key teaching that you'll need to do for your patients, you should advise them to increase their fluid intake because of the drying effects. They can suck on candy for a dry mouth.

And then the ipratropium albuterol combination, which is DuoNeb, is contraindicated for patients who have a peanut allergy. So that's something to keep in mind as well.

Okay. In my next video, we will be talking about corticosteroids, both inhaled and nasal. We'll be talking about leukotriene receptor antagonists as well as antitussive medications. So hang in there with me and we will get through these medications together!


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