Bronchodilators and Antimuscarinics Flashcards
(43 cards)
Which limb of the nervous system causes bronchodilation?
By stimulating the sympathetic or blocking the parasympathetc.
What is adrenergic stimulation?
Stimulation of the sympathetic nervous system.
What are beta-2 receptors?
G-protein receptors that are responsible for smooth muscle relaxation. SYMPATHETIC BRONCHODILATION.
How do beta-2 receptors cause bronchodilation?
They are G-proteins that when stimulated go on to stimulate adenyl cyclase which converts ATP into cAMP. cAMP increases activation of protein kinase A which prevents myosin and actin interaction, causing smooth muscle relaxation.
What are catecholamines?
A class of aromatic amines (neurotransmitters) like epinephrine and norepinephrine that cause sympathetic stimulation throughout the body.
What breaks down catecholamines?
catechol O-methyltransferase (COMT).
How do epinephrine and norepinephrine cause bronchodilation?
By stimulating SYMPATHETIC (beta-2) receptors.
How do we extend the half-life of catecholamine drugs?
Because they are metabolized by COMT, we can change the structure so that COMT cannot recognize and break down the drug.
What are SABA drugs and what are they used for?
Short acting beta adrenergics (agonists) and they are used as rescue or reliever drugs.
Which isomer of salbutamol is responsible for bronchodilation and how does that help us?
The R-isomer; there is an R-isomer only formula called levosalbutamol so that there are more molecules that are able to cause bronchodilation.
How long do LABA drugs last?
12-24 hours
What are some other names for muscarinic antagonists?
- antimuscarinics
- cholinergic blockers
- parasympatholytics
What are the two primary effects of parasympathetic innervation?
Bronchoconstriction and an increase in mucous production.
What are the main parasympathetic neurotransmitters?
Acetylcholine (ACh) which stimulates muscarinic 3 (M3) receptors.
What enzyme terminates the action of ACh?
Acetylcholinesterase.
Which nerve innervates the lungs?
The vagus nerve.
What are the three muscarinic receptors and where are they found?
M1: parasympathetic ganglia
M2: heart and postganglionic parasympathetic nerves
M3: airway smooth muscle and submucosal glands.
What muscarinic receptor do we tend to target?
M3
What happens when M3 receptors are stimulated?
A chain effect is set off, the end result of which is Ca2+ rushing into cells causing smooth muscle contraction.
What is the afferent signal caused by irritants in the airway transmitted by?
C fibres
What is the only common short acting muscarinic antagonist?
Ipratropium bromide (atrovent).
Describe the duration, use, delivery, and MOA of Aclidinium (Tudorza Genuair).
12 hrs, step-up medication, DPI, LAMA
Describe the duration, use, delivery, and MOA of Salbutamol (Ventolin)
<6 hrs, tx of acute issues, MDI, DPI, SVN, IV, oral, and is a SABA.
What is levosalbutamol?
A form of salbutamol that contains only the R-isomer (active isomer; S-isomer is inactive).
