Pharmacology - respiratory drugs = ASTHMA ,COPD

Question 1

what are the three classification of anti-asthma drugs ?

3

Answer 1

1-Symptomaic bronchodilators = B2 adrenoceptors, Anticholingerics ( M1 muscarinic receptor ANTagonist)

2- Prophylactic (prevents inflammation ) ie: corticosteroids

3-Anti-inflammatory resolve inflammation ie : leukotriene receptor antagonist

Question 2

How do B2 Selective agonist work

8

Answer 2

1) G-protein coupled receptor
2) SABA (short acting ) = ACUTE RELIEF
3) LABA (long acting = preventor inhaler
4) medication of choice

Pharmacology :

1) the agonist causes an increase in adenyl cyclase, hence cAMP , hence activation of protein kinase meaning :
- myosin light chain kinase = inhibited so contraction doesn’t occur = bronchodialation
- Ca2+ dependant K+ channels = K+ OUT the cell and LESS Ca2+ IN THE CELL = less contraction which leads to bronchodilation

Question 3

How do muscarinic Antagonists work?
(4)
what are they used to treat?

Answer 3

1- Effect parasympathetic system which means that vasoconstriction is prevented
2- Block the receptors so that IP3 and DAG meaning Ca2+ levels in cell are lower , Protein kinase C is not activated = less contraction !
3-better in COPD + episodes x bronchospasm
4-no arrhythmias but causes dry mouth

Question 4

How do xanthines work?
(4)
how it taken 
release =slow or fast?
what enzyme does it affect
why is it less used now?

Answer 4

1-( prevents diaphragm fatigue )=bronchodilator
The major pharmacologic actions of the xanthines are inhibition of tissue phosphodiesterase( these break down cAmp)
-> increases cellular cyclic AMP levels by inhibition of its breakdown and metabolism.
The xanthines also are adenosine receptor antagonists
=bronchodilator
Unknown why It works
2-oral and slow release but narrow therapeutic window
3-Effects P450 liver enzyme metabolism
4-has many drug interaction so isn’t widely used now

Question 5

How do corticosteroids work?
(3)
-how are they taken?
-what do they do?

Answer 5

1-Inhaled by oral preparation
2-inhibit phospholipase A and Cox -2 (PROMOTES Inflammation , and hence mucous production )
3- works in nucleus –>binds to DNA–>transcription factor change–>change in protein made =long lasting and slow acting
-they increase anti inflammatory proteins
-they decrease pro inflammatory proteins

Question 6

how do leukotriene receptor antagonists work? –ast
(3)
-when are they used?
-advantages + disadvantages

Answer 6

1-Used to treat excersize and antigen & aspirin induced asthma
ie: montelukast , zafirlukast LTD4 receptor
+ well tolerated and less side effects
-less effective than steroid
3-reduces inflammation by stabilising mast cells+bronchodilator

Question 7

how do you treat copd?
(4)
general , think lifestyle

Answer 7

1- treatment + tell them to stop smoking
2-pneumoccocal , influenza vaccines
3-pulmonary rehab +self management plan
4-optimise treatments for symptoms

Question 8

what is the order of prescribing medicine for COPD?

6

Answer 8

1- NO ASTHMA SYMPTOMS :
offer SABA , SAMA, –>LABA,LAMA
train with inhaler technique

2- ASTHMA symptoms SABA,SAMA–>LABA+corticosteroids –>LAMA+LABA+ICS

specialist training requires prescription of :
1-phospodiesterase inhibitors ie: theophylline and Roflumilast ( increased cAMP = increased bronchodilation)

2- Mucolytic + kinetic agents mainly carbocysteine = decreases the hyper secretion of the glycoproteins

Question 9

how do the phosphodiesterase inhibitors work?

2

Answer 9

• phosphodiesterase = normally breaks down and clears away cAMP , a low level of cAMP=>increased ca2+ + contraction
• INHIBITOR = LESS CAMP= DILATION AND RELAXATION

Question 10

How do mucolytics work ?

2

Answer 10

• decreases hypersecretion of the glycoproteins , and this makes mucous less thick and sticky = easier to cough up
• disulfide bonds are broken x high Mr molecules = reduced viscosity !