TRC: Beta-agonists for asthma

ß-agonists

Endogenous norepinephrine can stimulate α1, α2, β1 and β2 receptors. Most drugs are created to be either agonists or antagonists that are more selective for one or two receptors. However, no substance so far has shown 100% selectivity. β-agonist agents are more selective for the β-receptors.

β1-receptors are abundant in the circulation and skeletal muscle, β2 in smooth muscle (particularly in the respiratory tree).

Commonly used drugs of this group are ephedrine, salbutamol, salmeterol, formoterol, and terbutaline.

The β-receptors in airways are β2 type.

Extra info: This is an important physiological distinction for pharmacology. If you give the β-agonist by the inhaled route, then you will only affect the local β-2 receptors. If you give the drug systemically, you can effect β1 and β2 receptors throughout the body (e.g. β1 receptors in cardiac muscle).

Option explanation:

true

false

Many tissues contain β-receptors.

Extra info: β-receptors are located in many parts of the body including the heart, eye, bladder, lungs, smooth muscle, etc.

Option explanation:

true

false

To induce bronchodilation, a patient with asthma is treated with a combination of salbutamol (beta-2 agonist) and ipratropium (antagonist of the muscarinic acetylcholine receptor.) Indicate for salbutamol what type of ligand it is for the autonomic nervous system.

Option explanation:

parasympaticomimeticum

parasympaticolyticum

sympaticomimeticum

sympathicolyticum

To induce bronchodilation, a patient with asthma is treated with a combination of salbutamol (beta-2 agonist) and ipratropium (antagonist of the muscarinic acetylcholine receptor.) Indicate for ipratopium what type of ligand it is for the autonomic nervous system.

Option explanation:

parasympaticomimeticum

parasympaticolyticum

sympaticomimeticum

sympathicolyticum