Asthma Treatment: Beta Adrenoceptors Effects

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Questions and Answers

What is the primary effect of adrenoceptor agonists binding to Beta Adrenoceptors in relation to asthma treatment?

Stimulate the formation of intracellular cAMP (correct)

Enhance release of bronchoconstricting mediators

Promote airway smooth muscle contraction

Increase bronchoconstriction

Which of the following describes the result of increased intracellular cAMP in airway smooth muscle?

Increased production of bronchoconstricting mediators

Inflammation of airway tissues

Airway smooth muscle relaxation (correct)

Bronchoconstriction

What role do mast cells play in the context of asthmatic reactions?

Stimulate airway smooth muscle contraction directly

Release bronchoconstricting mediators (correct)

Reduce production of cAMP in airway cells

Increase airway resistance

What is the function of sympathomimetic agents in managing asthma symptoms?

Relax airway smooth muscles (A) Signup and view all the answers

In asthma management, what is the consequence of stimulating AC via beta adrenoceptor activation?

Increased formation of intracellular cAMP (B) Signup and view all the answers

What cause was identified for the increased asthma mortality rate in the UK in the mid-1960s?

Cardiac arrhythmias from isoproterenol (D) Signup and view all the answers

What is a reason for the current rarity of inhaled isoproterenol for asthma treatment?

It is associated with serious cardiac side effects. (D) Signup and view all the answers

Which receptor does isoproterenol primarily act on to facilitate its effects?

Beta-2 adrenergic receptor (A) Signup and view all the answers

What was a common misconception about the use of isoproterenol in asthma treatment?

It was thought to be safe for long-term use. (C) Signup and view all the answers

Which of the following statements about isoproterenol is true?

It can cause cardiac arrhythmias when used in high doses. (D) Signup and view all the answers

What is the primary route of administration for the substances mentioned?

Inhaled or oral administration (D) Signup and view all the answers

How does the duration of action of the mentioned substances compare to epinephrine or isoproterenol?

Longer duration of action (C) Signup and view all the answers

Which of the following statements is true regarding the effectiveness of these substances?

They are effective after oral or inhaled administration (C) Signup and view all the answers

What characteristic distinguishes these substances from epinephrine and isoproterenol?

They have a longer duration of action (A) Signup and view all the answers

In what way do the mentioned substances provide advantages in administration?

They allow for convenient oral or inhaled use (A) Signup and view all the answers

What is the primary reason for choosing levalbuterol over the racemic mixture of albuterol?

It is a purified isomer. (A) Signup and view all the answers

What is a common misconception regarding the efficacy of levalbuterol compared to racemic albuterol?

Both have the same efficacy in treating asthma. (D) Signup and view all the answers

Which of the following is a long-acting β2-selective agonist mentioned?

Salmeterol (B) Signup and view all the answers

What potential benefit does levalbuterol claim over racemic albuterol?

Better tolerance in children. (C) Signup and view all the answers

What has meta-analyses revealed about the toxicity of levalbuterol compared to racemic albuterol?

Both have comparable toxicity levels. (A) Signup and view all the answers

What is the meaning of 'التان من الساليدات' in English?

The conclusion of the ladies' (C) Signup and view all the answers

Which phrase indicates the completion of a section?

ي هيك خلصنا (A) Signup and view all the answers

What does the number '12' signify in the provided content?

A pagination marker (D) Signup and view all the answers

What can be inferred about the discussion from the phrase 'هيك خلصنا البارت'?

The discussion has been concluded (B) Signup and view all the answers

In the context provided, what is likely the main focus of the content?

Recap of the discussion (A) Signup and view all the answers

What is roflumilast approved for?

Reducing exacerbations of COPD (A) Signup and view all the answers

Which treatment has largely replaced theophylline for asthma?

Inhaled adrenoceptor agonists (A) Signup and view all the answers

Which of the following is NOT a reason for the decline in the use of theophylline?

It is no longer available on the market. (A) Signup and view all the answers

What is the main function of PDE4 inhibitors like roflumilast?

They reduce exacerbations of COPD. (D) Signup and view all the answers

What type of agents are now preferred for chronic asthma?

Inhaled anti-inflammatory agents (D) Signup and view all the answers

Study Notes

Pharmacology (2)

This document covers Pharmacology (2), including book notes, records, translations, important notes, and mind maps/illustrations.
A specific section on asthma part 2 is included.

Sympathomimetic Agents

Adrenoceptor agonists bind to β-ARs, stimulating AC and increasing intracellular cAMP.
This relaxation of airway smooth muscle inhibits the release of bronchoconstrictors from mast cells.
Microvascular leakage is also inhibited, and mucociliary transport is enhanced.
Side effects include tachycardia, skeletal muscle tremors, and decreased serum potassium levels.
Inhalation delivery is preferred for greatest local effect and reduced systemic toxicity.
Albuterol and other β2-selective agents are widely used in asthma treatment.
Epinephrine and isoproterenol have reduced use due to their effects on cardiac contraction (mediated by β1 receptors).
Aerosol deposition depends on particle size, breathing pattern, and airway geometry.

Epinephrine

An effective and fast-acting bronchodilator.
Maximal bronchodilation is achieved 15 minutes post-inhalation, lasting 60-90 minutes.
Stimulates β1, β2, and α receptors, leading to potential side effects like tachycardia, arrhythmias, and angina worsening.
Primarily used for acute anaphylaxis-related vasodilation and bronchospasm.
It's largely replaced by other β2-selective agents in asthma treatment.
Ephedrine is a less potent alternative with longer duration and oral activity, though now less frequently used.

Isoproterenol

A potent β1 and β2 bronchodilator.
Rapid maximal bronchodilation (within 5 minutes) and extended duration (60-90 minutes) post-inhalation.
Increased asthma mortality rate in the UK in the mid-1960s linked to cardiac arrhythmias.
Now rarely used for asthma due to this risk.

Beta 2-Selective Drugs

Albuterol, terbutaline, metaproterenol, and pirbuterol are metered-dose inhalers.
Produce bronchodilation comparable to Isoproterenol (maximal within 15-30 minutes, lasting 3-4 hours).
Primarily R isomer; R isomer activates the β2-agonist receptor.
Available in oral form in addition.

Side Effects

Skeletal muscle tremor, nervousness, occasional weakness are possible side effects.
Oral administration is less desirable than inhalation due to more pronounced side effects.
Parenteral terbutaline may be used in premature labor cases to inhibit uterine contractions.

Methylxanthine Drugs

Theophylline, theobromine, and caffeine are the key methylxanthines sourced from beverages.
In high concentrations, they inhibit multiple phosphodiesterase (PDE) enzymes.
This increases intracellular cAMP and cGMP levels, affecting smooth muscle relaxation, cardiac function, and immune responses.
PDE3 inhibition is critical for smooth muscle relaxation, and PDE4 inhibition decreases immune cell activation.
Roflumilast, a selective PDE4 inhibitor, is FDA-approved for COPD but not asthma.

Other Notes

Theophylline, once a key asthma treatment, is now less commonly used because of its narrow therapeutic index, frequent drug interactions, and associated toxicities (nausea, vomiting, tremors, arrhythmias).
It is still used in some countries due to its lower cost.
Adenosine receptors inhibition helps in treating asthma symptoms.
Corticosteroids, along with low-dose theophylline, can act through histone deacetylase recruitment for increased inflammatory response reduction.

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Description

This quiz explores the role of beta adrenoceptors in asthma treatment and the effects of adrenoceptor agonists, including cAMP levels and mast cell involvement. Test your knowledge on sympathomimetic agents and their use in managing asthma symptoms.