Drugs and Asthma

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Questions and Answers

What is a primary function of long-acting muscarinic receptor antagonists (LAMAs)?

Activate beta2-adrenoceptors

Block muscarinic receptors (correct)

Enhance airway inflammation

Increase phosphodiesterase activity

Which statement regarding theophylline is accurate?

Has no central nervous system effects

Is an effective water-soluble oral form of medication

Functions as a phosphodiesterase inhibitor (correct)

Acts solely as a leukotriene receptor antagonist

What is a notable adverse effect associated with prolonged use of glucocorticoids like prednisolone?

Edema

Enhanced immune response

Adrenal suppression (correct)

Increased synthesis of IL-2

How does prednisolone exert its anti-inflammatory effects?

By inhibiting IL-2 transcription Signup and view all the answers

Which of the following drugs is classified as a short-acting β2-adrenoceptor agonist (SABA)?

Salbutamol Signup and view all the answers

What is the therapeutic window for theophylline plasma levels?

10-20 mg/L Signup and view all the answers

What potential risk is associated with high levels of theophylline?

Convulsions and arrhythmias Signup and view all the answers

What is the primary mechanism of action for inhaled corticosteroids in asthma management?

Inhibiting the release of inflammatory mediators from mast cells Signup and view all the answers

Which mechanism is activated by beta2-adrenoceptor agonists?

Relaxation of bronchial smooth muscle Signup and view all the answers

Which of the following drugs is a leukotriene receptor antagonist?

Montelukast Signup and view all the answers

In the context of severe asthma, which factor contributes significantly to disease management?

Potential for eosinophil involvement Signup and view all the answers

Which of the following drugs acts as a long-acting muscarinic antagonist (LAMA)?

Ipratropium Signup and view all the answers

What is the primary role of β2-adrenoceptor agonists in asthma treatment?

Preventing bronchospasm Signup and view all the answers

Which enzyme is responsible for the breakdown of adrenaline and other catecholamines in the body?

Catechol-O-methyltransferase (COMT) Signup and view all the answers

Which of the following is NOT a potential benefit of using a spacer with an inhaled medication?

Increased speed of action Signup and view all the answers

Which of the following statements about theophylline is TRUE?

It is a methylxanthine with bronchodilator properties Signup and view all the answers

Which of the following is a correct statement about long-acting β2-adrenoceptor agonists (LABAs)?

LABAs can cause muscle cramps as a potential side effect. Signup and view all the answers

Which of the following medications is a leukotriene receptor antagonist?

Montelukast Signup and view all the answers

What is the primary mechanism of action for leukotriene receptor antagonists in asthma treatment?

Inhibiting the production of leukotrienes, which contribute to inflammation. Signup and view all the answers

What is the main function of long-acting muscarinic cholinoceptor antagonists (LAMAs) in asthma treatment?

Blocking the action of acetylcholine at muscarinic receptors, leading to bronchodilation. Signup and view all the answers

Which of the following statements is TRUE regarding the use of inhaled corticosteroids (ICS) in asthma treatment?

ICS can increase the risk of asthma-related deaths when used alone. Signup and view all the answers

Which of the following is a common side effect of montelukast, a leukotriene receptor antagonist?

Diarrhea Signup and view all the answers

Which of the following statements is TRUE about the relationship between adrenaline and catechol-O-methyltransferase (COMT)?

COMT breaks down adrenaline, decreasing its effectiveness. Signup and view all the answers

Which of the following medications is a long-acting muscarinic cholinoceptor antagonist (LAMA)?

Tiotropium Signup and view all the answers

Study Notes

Long-acting Muscarinic Receptor Antagonist (LAMA)

Tiotropium is a LAMA that acts as a bronchodilator and respiratory stimulant.
It has two central mechanisms: phosphodiesterase inhibitor, which increases cAMP, and adenosine receptor antagonist.
It activates histone deacetylase (HDAC), reversing resistance to corticosteroids induced by oxidative stress.
Extended release formulation allows for twice-daily dosing, with a therapeutic window of 10-20 mg/L plasma levels.
However, it can saturate liver metabolism, leading to potential convulsions, arrhythmia, and drug interactions.

Theophylline

A bronchodilator and respiratory stimulant with two central mechanisms: phosphodiesterase inhibitor, increasing cAMP, and adenosine receptor antagonist.
It activates histone deacetylase (HDAC), reversing resistance to corticosteroids induced by oxidative stress.
Extended release formulation allows for twice-daily dosing, with a therapeutic window of 10-20 mg/L plasma levels.
However, it can saturate liver metabolism, leading to potential convulsions, arrhythmia, and drug interactions.
Aminophylline is a water-soluble, injectable form of theophylline.

Corticosteroids

Prednisolone is an oral corticosteroid that works at the level of transcription.
It has anti-inflammatory and immunosuppressive effects.
Mechanisms include:
- Lipocortin inhibits AA release and IL-2 transcription.
- Inhibits clonal expansion of T cells and mast cells.
- Decreases vascular permeability and increases β2-adrenoceptor expression.
Adverse effects include adrenal suppression, which requires slow withdrawal of steroids.

Severe Asthma

Characterized by constant breathlessness, inability to perform simple tasks, and frequent attacks requiring oral steroids.
Affects around 100,000 adults in the UK.
Asthma attacks can occur without warning, leading to hospitalization and, in severe cases, death.

Drug Treatment of Asthma

1. Intermittent Reliever Therapy: Short-acting β2-adrenoceptor agonists (SABA) for quick relief.
1. Regular Preventer (Maintenance) Therapy: Low-dose inhaled corticosteroids for long-term treatment.
1. Initial Add-In Therapy: Leukotriene receptor antagonists (oral) or long-acting β2-adrenoceptor agonists (inhaled).
1. Additional Controller Therapy: Theophylline (oral) or long-acting muscarinic antagonists (inhaled).
1. Continuous Corticosteroid (Oral) Therapy: Prednisolone for severe asthma.

Inhalers, Spacers, and Nebulisers

Devices used for administering asthma medications.

SABA (Short-Acting β2-Adrenoceptor Agonists)

Salbutamol, terbutaline, and adrenaline are examples of SABA.
Mechanism of action: binding to β2-adrenoceptors, causing bronchodilation.
Effects:
- Dilates bronchioles, providing immediate relief.
- Maximum effect occurs at 30 minutes, with a duration of 3-5 hours.
- May also inhibit mediator release from mast cells and TNF-α release from monocytes.

Leukotriene Receptor Antagonists (Oral)

Montelukast is an oral asthma agent that antagonizes the CysLT-1 receptor, inhibiting lung inflammation.
Adverse effects include diarrhea, gastrointestinal discomfort, nausea, and vomiting.

Long-Acting β2-Adrenoceptor Agonists (LABA)

Salmeterol and formoterol are examples of LABA.
Maintenance dosing (twice daily) is used, but not for acute use.
Should be used with inhaled corticosteroids, as using alone may increase asthma-related deaths.
Can induce muscle cramps.

Maintenance and Reliever Therapy (MART)

Combines beclometasone and formoterol for maintenance and reliever therapy.

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Description

Learn about the mechanisms of action of Long-Acting Muscarinic Receptor Antagonist (LAMA) tiotropium, a bronchodilator and respiratory stimulant. Understand its central mechanisms and effects on histone deacetylase and corticosteroids.