Chapter 6 Adrenergic Bronchodialators Flashcards
What is alpha receptor stimulation?
Causes vasoconstriction and vasopressor effect.
Can provide decongestion in nasal passage
What is the asthma paradox?
What are theories of it?
Increased asthma morbidity despite advances in asthma research.
- patient feels improvement but doesn’t maintain it and starts approaching triggers
- misuse of beta adrenergic drugs in lieu of corticosteroid to treat asthma
What is a beta 1-receptor stimulation?
Increased heart rate and contractility
What is a beta 2 stimulation?
- Bronchodilation
- some inhibition of inflammatory mediators
- stimulation of mucous clearance.
What is a bronchospasm?
Narrowing of the bronchial airways
What is a catecholamine?
Compound similar to epinephrine
-sympathomimetic
What is down regulation?
Desensitization to beta agonists at beta receptor sites. causes by reduction of beta receptor sites
Why do we use adrenergic bronchodilators?
To relax the airway smooth muscle in the presence of reversible airflow obstruction associated with acute and chronic asthma, bronchitis, emphysema, bronchiectsis
What should you use for ACUTE reversible airflow obstruction?
SABA
When would you use a LABA?
- Maintenance of bronchodilation
- control of bronchospasm
- night symptoms of asthma
When would you use a racemic epinephrine?
4 reasons
Vasoconstriction effects for
- croup
- post extubation swelling
- control airway bleeding
- bronchiolitis
How long do ultra short acting beta agonists last?
3 hours or less
How long do short acting beta agonists last?
4 to 6 hours
How long do long acting beta agonists last?
12 hours
Describe the isomer of a beta adrenergic bronchodilator.
There is a left and a right isomer
- right isomer is active on beta airway receptors
- left isomer is inert, also called the sinister isomer.
What is the drug that is the first single isomer adrenergic bronchodilator?
Describe the isomer.
Levalbuterol
Its a single right isomer.
What does epinephrine drug excite in the body?
What are some issues with it?
- stimulates alpha and beta receptors
- not beta specific, high chance of side effects
- rapid onset due to COMT metabolization
What is the beta 2 keyhole specificity theory?
The larger the side chain of the catechol base, the better the more beta 2 specific it is.
What inactivates catecholamines?
COMT
Why isn’t it advisable to take catecholamines orally?
Because of rapid inactivation of COMT. Which is found in the liver and kidneys.
-it’s inactivates by the gut and liver.
What is a resorcinol agent?
Give an example
It is a non-catacholamine. It is a modified catacholamine that is not inactivated by COMT.
-metaproterinol
What is a saligenin?
Give some examples
It is a non-catacholamine agent, modified from a catacholamine.
But is a more beta 2 specific drug. Less side effects.
-albuterol
-pirbuterol
-levalbuterol
What is an adrenergic bronchodilator?
Agent that stimulates sympathetic nervous fibers
-which allows relaxation of lung smooth muscle
beta 2 agonist
Is albuterol only a SABA?
No
-there is an “Extended release” albuterol tablet.
Called Vospire ER
Drugs included in the saligenin class
4 drugs
1) albuterol (proventil, ventolin)
2) pirbuterol (Maxair)
3) salmeterol (Serevent)
4) levalbuterol (xopenex)
How long is the onset for catecholamines?
1-3 mins
How long is the onset for non-catecholamines like resorcinols and saligenins?
With 1 exception…
5-15 mins
Except for salmuterol (more than 20 mins)
How do you assess if beta agonist therapy would be effective for your patient?
- presence of reversible airflow resulting from primary bronchospasm
- obstruction secondary to an inflammatory response or secretion either acute or chronic
How can you test a patient’s susceptibility to beta agonist therapy?
Pre therapy 3 things
- Measure flowrates with the peak flow
- perform respiratory assessment auscultations
- assess pulse before during and after treatment. 20% increase is not good
Contraindications to beta agonist therapy
3 reasons
- regular long-term use of Saba and LABA not recommended
- patients with cystic fibrosis, COPD, and asthma may be less responsive
- patients with heart problems should be monitored
What is the mechanism of action for racemic epinephrine?
3 things
- Racemic epinephrine works by stimulation of the α-adrenergic receptors (mucosal vasoconstriction)
- decreased fluid in the airway (subglottic edema) and
- by stimulation of the β-adrenergic receptors causing relaxation of the bronchial smooth muscle.
