Bronchodilator and Anti-inflammatory Drugs in the Treatment of Asthma Flashcards
What are the two types of drugs used in Asthma?
Relievers, and controllers/preventors
How do Relievers work?
They act as bronchodilators
Examples of relievers
Short acting B2-adrenoceptor agonists. Long acting B2-adrenoceptor agonists. CysLT1 receptor antagonists.
How do controllers/preventers work?
They act as anti-inflammatory agents that reduce airway inflammation.
Examples of controllers/preventors
Glucocorticoids - cromoglicate. Humanised monoclonal IgE antibodies.
What is the comparison with aerosol and oral in pharmokenetics?
Aerosol - Slow absobtion from lung surface and rapid systemic clearance
Oral - Good oral absorbtion (with exceptions) and slow systemic clearance.
What is the comparison with aerosol and oral in dose.
Aerosol - Low dose delivered rapidly to target.
Oral - High systemic dose necessary to achieve an appropriate concentration in the lung.
What is the comparison with aerosol and oral in systemic concentration of drug?
Aerosol - low
Oral - High
What is the comparison with aerosol and oral in incidence of adverse effects.
aerosol - Low
Oral - High (but depends on drug)
What is the comparison with aerosol and oral on distribution of drug.
aerosol - reduced in severe airways disease
oral - unaffected by airways disease.
What is the comparison with aerosol and oral in Compliance
aerosol - Good with bronchodilators, less so with anti-inflammatory drugs.
Oral - good
What is the comparison with aerosol and oral in ease of administration
aerosol - difficult for small children and infirm people (old/feeble)
Oral - good
What is the comparison with aerosol and oral in effectiveness
Aerosol - good in mild to moderate disease
Oral - good even in severe disease.
What do B2-adrenoceptor agonist do?
Act as physiological antagonists of all spasmogens. Prevents the mechanism of airway smooth muscle contraction.
What are the three clasifications that B2 - adrenoceptor agonists come under?
Short-acting(SABA) , long-acting(LABA) and ultra long-acting(ultra-LABA)
When are SABA used?
First line of treatment for mild or intermittent asthma. They are relievers as they are taken when needed.
How are SABA administered and in what situation?
They are usually administered by inhalation via metered dose/dry powder devices (lessens systematic effect.
In children they use oral and IV for emergencies.
How rapidly do SABA act?
within 5 minutes when inhaled with the maximal effect within 30 minutes. This will last for 3-5 hours.
Apart from relax the bronchial smooth muscle, what else does SABA do?
Increase mucus clearance and decrease mediator release from mast cells and monocytes.
Given 2 examples of SABA
Salbutamol, terbutaline
Adverse effects of SABA?
Very few due to unwanted systemic absorption when administered by inhalation. A fine tremor can happen.
However, tachycardia, cardiac dysrythmia and hypokalaemia can occur.
Give 2 examples of LABA
Salmeterol and formoterol
When are LABA useful and not useful.
Useful for nocturnal asthma as they act for aprox 8 hours.
Not recommended for acute relief of bronchospasm (salmeterol is too slow - not formoterol tho)
What does LABAs need to be administered with?
glucocorticoid
Which is better, non-selective or selective B2-adrenoceptor
The use of selective B2-adrenoceptors can reduce potentially harmful stimulation of cardiac B1-adrenoceptors.
Non-selective B-adrenoceptors antagonists in asthmatic patient is contraindicated (risk of bronchospasm)
What does a cysteinyl leukotriene (CysLTs) receptor antagonists do?
They act as a competitive inhibitor for the cysLT1 receptor.
What are the 3 cysLTs are derived from mast cells and inflammatory cells and what do they do?
LTC4, LTD4 and LTE4. They cause smooth muscle contraction, mucus secretion and oedema.
How are CysLT1 receptor antagonists effective?
They are effective as a add on therapy against early and late bronchospasms in mild persistent asthma. They are usually with other medication (corticosteriods in severe conditions)
What types of asthma are CysLT1 receptor agonist effective against?
Antigen-induced and exercise-induced bronchospasms
How are CysLT1 receptor agonist administrated?
Orally
What are cysLT1 receptor agonist not recommended for?
Relief of acute severe asthma
What are the symptoms of cysLT1 receptor agonists?
They are generally well tolerated, although headache and gastrointestinal setup have been reported.
Give two examples of cysLT1 receptor agonists
Montelukast and Zafirlukast
Name a commonly used group of Xanthines
Methylxanthines
Give two examples of methylxanthines
Theophylline and aminophylline
What is methylxanthine in?
Coffee, tea and chocolate-containing beverages.
What is the possibility of what methylxanthines do?
They inhibit PDE which inhibits the potentiating the action of cAMP in Airway smooth muscle in the B2-adrenoceptor pathway.
