Drugs used for asthma Flashcards
What is meant by status asthmaticus?
It is a severe emergency condition of asthma that requires immediate and urgent treatment, hence the use of inhalers with a very rapid onset like salbutamol or IV drugs
Describe the pathobiology of asthma
Immediate Phase:
This phase triggers bronchial hyperreactivity and spasms. The primary goal here is to relieve the bronchospasm.
Delayed Phase:
When chemotaxins activate inflammatory cells, it leads to a delayed phase characterized by increased hyperreactivity, bronchospasm, and airway inflammation. There is also mucus production and inflammatory cells infiltrate the bronchial walls.
Therefore, in treating obstructive lung diseases, the therapeutic approach focuses on targeting bronchospasm, inflammation, or both.
What triggers bronchodilation?
- The sympathetic system
1) cAMP
- Triggered by the release of nor/and epinephrine
What triggers bronchoconstriction?
- The parasympathetic system
1) Acetylcholine
2) Adenosine
What inhibits bronchoconstriction?
1) Theophylline
2) Muscarinic antagonists
What type of sympathetic receptors are found in the bronchi?
B-2 receptors
What type of parasympathetic receptors are found in the bronchi?
Muscarinic-1 receptor
What are some examples of (SYMPATHOMIMETIC AGENTS)
Beta2-Selective Drugs?
Short-acting:
1) Salbutamol (short-acting)
2) Pirbuterol
3) Terbutaline
4) Metaproterenol
Long-acting: (not used for acute attacks)
5) Salmeterol
6) FORMOTEROL
Ultra-Long-Acting:
7) Indacaterol
8) Vilanterol
- They reverse bronchospasm
- They are effective in the immediate phase (acute phase) not the delayed phase
What are the different families of medications to treat asthma?
1) SYMPATHOMIMETIC AGENTS
Beta2-Selective Drugs
2) METHYLXANTHINE DRUGS
3) LEUKOTRIENE PATHWAY INHIBITORS
4) ANTIMUSCARINIC AGENTS
5) Inhaled CORTICOSTEROIDS (ICS)
6) TARGETED (MONOCLONAL ANTIBODY) THERAPY
7) CROMOLYN & NEDOCROMIL
What is the mechanism of action of (SYMPATHOMIMETIC AGENTS)
Beta2-Selective Drugs?
1) Action: Bronchodilation
2) MOA: it decreases the calcium-mediated contraction in the bronchioles, by increasing cAMP which activates protein kinase-A, PKA will inhibit MLCK “myosin light chain kinase” (a mediator of contraction)
How are the (SYMPATHOMIMETIC AGENTS) Beta2-Selective Drugs absorbed and eliminated by the body?
1) Absorbed by inhalation
2) Excreted unchanged
What are the clinical uses of (SYMPATHOMIMETIC AGENTS)
Beta2-Selective Drugs?
1) Acute asthma attack
2) Preventing exercise-induced asthma attacks
What is the first-line drug for acute asthma attacks?
SYMPATHOMIMETIC AGENTS Beta2-Selective Drugs
When do we use the LABA
In patients needing prolonged broncho-dilating therapy
Why should we administer Inhaled corticosteroid with ULTRA-LABA
Because they can mask the symptoms of bronchial inflammation
What are some examples of METHYLXANTHINE DRUGS?
1) Theophylline (aminophylline i.v. form)
2) Theobromine
3) Caffeine
4) Roflumilast
What is the mechanism of action of the methylxanthine drugs?
The increase in the amount of cAMP by inhibiting phosphodiesterase PDE4, inducing bronchodilation
Which drug is a selective PDEE inhibitor?
Roflumilast
When is roflumilast indicated?
It is indicated when we need to decrease the exacerbation of severe COPD
Which class of drug is the second-line treatment for chronic asthma, that is not controlled by B2-agonist?
Methylxanthine drugs
Can we add theophylline to the inhaled B2 agonist?
No, Because it does not increase the bronchodilator response and may increase their side effects
What are the adverse effects of methylxanthine drugs?
1) Tachycardia
2) Dysrhythmia
What are some examples of leukotriene pathway inhibitors?
- Leukotriene receptor antagonist
1) Montelukast
2) Zafirlukast
- Lipoxygenase enzyme inhibitor
3) Zileuton
Which leukotriene pathway inhibitor inhibits the lipoxygenase enzyme?
Zileuton
What is the mechanism of action of the leukotriene pathway inhibitors?
1) Inhibition of the lipoxygenase enzyme
2) Inhibition of the leukotriene receptor
- Inhibiting the action of LTC4, LTD4 & Histamine