Podcast
Questions and Answers
Which of the following is the primary method of administration for corticosteroids during a status asthmaticus attack?
Which of the following is the primary method of administration for corticosteroids during a status asthmaticus attack?
What are the potential systemic adverse effects of corticosteroids?
What are the potential systemic adverse effects of corticosteroids?
What mechanism do mast cell stabilizers employ to prevent asthma attacks?
What mechanism do mast cell stabilizers employ to prevent asthma attacks?
Which leukotriene modifier is known to be hepatotoxic and can elevate liver enzymes?
Which leukotriene modifier is known to be hepatotoxic and can elevate liver enzymes?
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Which of the following side effects is NOT commonly associated with inhalation corticosteroids?
Which of the following side effects is NOT commonly associated with inhalation corticosteroids?
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What is an appropriate indication for the use of cromolyn-like drugs?
What is an appropriate indication for the use of cromolyn-like drugs?
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Which substance is contraindicated in patients with bronchial asthma due to its potential to precipitate attacks?
Which substance is contraindicated in patients with bronchial asthma due to its potential to precipitate attacks?
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What is a noted effect of using leukotriene modifiers such as zafirlukast and monteleukast?
What is a noted effect of using leukotriene modifiers such as zafirlukast and monteleukast?
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Which class of drugs is primarily used for quick relief of asthma symptoms?
Which class of drugs is primarily used for quick relief of asthma symptoms?
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What is the primary mechanism of action for B2 selective agonists in asthma treatment?
What is the primary mechanism of action for B2 selective agonists in asthma treatment?
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Which of the following is NOT a possible adverse effect of B2 selective agonists?
Which of the following is NOT a possible adverse effect of B2 selective agonists?
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Which medication is primarily indicated for both acute bronchial asthma attacks and prophylaxis?
Which medication is primarily indicated for both acute bronchial asthma attacks and prophylaxis?
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What major risk is associated with high doses of theophylline?
What major risk is associated with high doses of theophylline?
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Which of the following statements about Ipratropium is correct?
Which of the following statements about Ipratropium is correct?
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How do corticosteroids primarily exert their effects in treating asthma?
How do corticosteroids primarily exert their effects in treating asthma?
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What is the preferred route of administration for short-acting B2 agonists?
What is the preferred route of administration for short-acting B2 agonists?
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What adverse effect might occur at levels greater than 15ug/ml of theophylline?
What adverse effect might occur at levels greater than 15ug/ml of theophylline?
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Which drug is commonly combined with a B2 agonist for enhanced therapeutic effect in asthma?
Which drug is commonly combined with a B2 agonist for enhanced therapeutic effect in asthma?
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Study Notes
Bronchial Asthma Presentation
- Presentation title: Bronchial Asthma
- Presenter: Dr. Mohamed Abdel Aziz
Bronchial Asthma Overview
- Bronchial asthma is a chronic respiratory condition characterized by inflammation and narrowing of the airways.
- An image displays a normal lung airway and an inflamed lung airway, highlighting the difference in the appearance of the airways in both states.
Lines of Treatment
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I-Quick relief medications:
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1-Bronchodilators:
- B2 selective agonists (e.g., Salbutamol, Salmeterol)
- B-non selective agonists (e.g., Epinephrine, Isoprenaline)
- Drugs inhibiting adenosine A1 receptors (e.g., Theophylline, methylxanthine)
- Drugs inhibiting cholinergic M3 receptors (e.g., Ipratropium)
- 2-Corticosteroids:
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1-Bronchodilators:
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II-Long term control medications (prophylaxis):
- Cromolyn-like drugs
- Leukotriene modifiers
- Note that these long-term medications are used in addition to the quick-relief medications.
Bronchodilators Mechanism of Action
- Bronchodilators work by acting on specific receptors (β2 and M3) in the lungs.
- An image shows the lungs and the corresponding receptors.
- β2 receptors activation leads to bronchodilation.
- M3 receptor blockage also leads to bronchodilation.
- PDE (phosphodiesterase) is the enzyme that breaks down Cyclic AMP
B2 Selective Agonists
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Members:
- Short-acting: Salbutamol, Terbutaline
- Long-acting: Salmeterol
- Route: Inhalation (MDI) is preferred for better results and fewer side effects compared to oral or parenteral administration.
Inhaled Bronchodilators
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Short-acting β2 agonist (SABA):
- Salbutamol (5 mg/hr) or terbutaline (10 mg/hr) administered via nebulizer or metered dose inhaler (MDI) with a spacer device.
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Inhaled anti-cholinergics (SAMA):
- Ipratropium bromide (0.5 mg).
Mechanism of Action (B2 Agonist)
- Stimulation of β2 receptors triggers a cascade of events that lead to smooth muscle relaxation, resulting in bronchodilation.
- The activation of Gs protein stimulates adenyl cyclase, increasing cyclic AMP. The subsequent decrease in intracellular calcium ions further relaxes the smooth muscle. This process directly relates to improved lung function.
- The result of stimulating the β2 receptor is shown.
- It is a mast cell stabilizer that prevents mediator release, playing a prophylatic role for bronchial asthma.
Adverse Effects of Bronchodilators
- Throbbing headache
- Tremors
- Tachycardia
- Tolerance (with large doses)
- Locked lung syndrome & hypoxia (with large doses)
- Constipation
- Hyperglycemia & hypokalemia (with IV administration)
Methylxanthines (Theophylline & Caffeine)
- Mechanism: Block adenosine A1 receptors, inhibiting phosphodiesterase, leading to increased cAMP.
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Pharmacological Actions:
- Smooth muscle relaxation (bronchodilation)
- Skeletal muscle contraction (e.g., diaphragm)
- Cardiac stimulation (positive inotropic & chronotropic)
- Central nervous system stimulation (e.g., delay fatigue, insomnia, respiratory stimulation)
Indications of Methylxanthines
- Bronchial asthma (acute attacks & prophylaxis)
- Generalized obstructive pulmonary disease (COPD)
- Cardiac asthma (bronchospasm due to heart failure)
- Biliary colic
- Migraine (used with ergot drugs to enhance absorption)
Adverse Effects of Methylxanthines
- Central nervous system (CNS) adverse effects (e.g., anxiety, headache, palpitations, vomiting) occur at 15 µg/ml
- Cardiovascular (CVS) adverse effects (e.g., hypotension-VD, palpitation) occur at 20 µg/ml
- Death can result from an extremely high dose of 40 µg/ml and can cause convulsion & arrhythmia
- Irritant properties of the drug can cause significant effects when used undiluted intravenously
- Prolonged use can result in adverse effects, such as:
- Phlebitis
- Proctatitis
- Peptic ulcers
- Constipation
- Cardiac arrest (from rapid IV administration)
Pharmacokinetics of Theophylline
- The metabolism of theophylline occurs in the liver.
- Increased doses are required for patients with highly active liver enzymes (e.g., smokers, children, individuals on enzyme inducers).
- Decreased doses are needed for patients with lower liver enzyme activity (e.g., cirrhosis, elderly, those with enzyme inhibitors).
Anticholinergic Drugs (Ipratropium)
- Mechanism: Blocking muscarinic receptors (M3), effectively antagonizing cholinergic effects. The effect is to induce smooth muscle relaxation and bronchodilation.
- Route: Inhalation is preferred due to a smaller dose and fewer side effects compared to atropine.
- Can be combined with B2 agonists.
Indications of Ipratropium
- Preferred in patients with intolerance to β2 agonists or xanthine derivatives.
- Patients with cardiac or thyrotoxic conditions are particularly suited for this choice.
- An option for these specific situations is a beneficial choice.
Adverse Effects of Ipratropium
- Delayed onset of effect
- Potential development of tolerance over time
Anti-inflammatory Drugs
- Hormones (Corticosteroids): Inhibit phospholipase A2, thus reducing inflammatory mediators like leukotrienes. The result is anti-inflammatory and immunosuppressive action.
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Non-hormone drugs (cromolyn-like drugs, leukotriene modifiers):
- Example: Cromolyn and nedocromil act as mast cell stabilizers, reducing mediator release. They also inhibit IgE production.
- Leukotriene modifiers (Zileuton, Zafirlukast, Montelukast) block leukotriene receptors and limit their effects. Leukotrienes are inflammatory mediators associated with asthma.
Indications of Corticosteroids
- Status asthmaticus (severe, resistant asthma attacks) are treated intravenously (IV).
- Prophylaxis for persistent asthma are treated by inhalation.
Adverse Effects of Corticosteroids
- Inhalation: Oral candidiasis, hoarseness of voice.
- Systemic: Adrenal suppression, osteoporosis, glaucoma, cataracts (IV/oral).
Cromolyn-like Drugs: Mechanism and Indications
- Mechanism: Mast cell stabilizer, inhibiting mediator release, and decreasing calcium channels also inhibiting IgE synthesis
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Indications:
- Asthma prophylaxis
- Allergic conjunctivitis, rhinitis
- Ulcerative colitis
Cromolyn-like Drugs Adverse effects
- Local: Wheezing, cough, (avoid during acute attack).
- Local: Nasal congestion, eye irritation.
Leukotriene Modifiers
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Mechanism: Inhibit 5-lipoxygenase enzyme, thus limiting leukotriene production.
- Alternative for steroid-resistant patients
- These drugs inhibit leukotriene production in the body.
- Not recommended for the acute episodes of asthma.
- Drugs: Zileuton, Zafirlukast & Montelukast (blocks LT receptors).
Treatment of Status Asthmaticus
- Acute, severe, and resistant asthma attacks respond well to the following treatments:
- Beta2-agonist by nebulizer
- IV hydrocortisone
- IV theophylline infusion
- Magnesium sulfate
- Supportive care (oxygen, antibiotics, mucolytics, hydration)
Drugs to Avoid in Asthma
- Beta-blockers (especially non-selective)
- Adenosine
- Cholinergic mimetics (e.g., neostigmine)
- Morphine & Curare (release histamine)
- NSAIDs (increase leukotrienes)
- Cromolyn without a β2-agonist
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Description
This quiz provides an in-depth overview of bronchial asthma, a chronic respiratory condition. It covers the characteristics of asthma, differences in airway appearance, and various lines of treatment including quick relief and long-term medications. Test your knowledge on the mechanisms and medications used in asthma management.
