Pharmacology Flashcards
b2-adrenoceptor agonist
eg. salbutamol (ventolin inhaler - asthma) short acting
act on b2-adrencpeotrs on bronchial smooth muscle - increase cAMP
- -reduce parasympathetic activity
- -rapid bronchodilatation + reversal of bronchospasm
- -cAMP - inhibits aggregation
prolonged use - receptor down regulation
—use with corticosteroids - reduce down regulation
long-acting b2-adrenoceptor agonist
LABA
eg salmeterol (long term prevention and control of asthma)
rate of onset is slow and retained near receptor for prolonged period
xanthines
eg. theophylline (asthma)
bronchodilators
not as effective as b-adrenoceptor agonist
aminophylline (iv emergency)
muscarinic m-receptor antagonists
eg. tiotropium in COPD
blocks parasympathetic bronchoconstriction
–inhalation - prevents side effects
limited value in asthma
corticosteroids
eg. beclomethasone in severe asthma
will take several days to have an effect
1) alter gene transcription to decrease cytokine production
2) lipocortin production - inhibit arachidonic acid release
- —inhibit PGs + LTs
Leukotriene receptor antagonist (LTRAs)
eg. montelukast (oral)
preventer - bronchodilator
inhibit LTs
add on therapy
IgE antibodies
eg. omaliumab
monoclonal antibody directed against free IgE
–prevents IgE binding to immune cells and causing inflam response
asthma treatment path
1) short acting b2-agonists plus regular inhaled steroid
2) trial of LABA, (or LTRA or xanthine if fails)
3) increase dose of inhaled steroid
4) add oral steroid
must step up if using salbutamol >2times weekly
COPD treatment path
1) short-acting b2-agonist
2) add short-acting antimuscarinic agent
3) addition of LABA
4) add inhaled steroid
5) add theophylline
6) oxygen therapy
NSAIDs and asthma
NO
may provoke asthma by increasing LT production
inhibit PGs so divert arachidonic acid down LT pathway
Diuretics/thiazides
reduction in circulating volume
reducing preload and after load - decrease in cardiac work
may vasodilator
inhibit Na+/Cl- reabsption in distal convoluted tubule
SIDE EFFECT - hypokalaemia
ACEi
eg. ramipril
VD, and reductions in salt and water retention
reduction in angiotensin II - meaning decrease VC and aldosterone
reduced aldosterone - reduction in salt and water retention - reduced circulating vol
side effects - cough due to build up of bradykinin (VD)
Angiotensin II receptor antagonist
eg. candesartan
VD
block action of AII at AT1 receptor
similar to ACEi - don’t given rise to cough
calcium channel inhibitors
eg. verapamil, DHPs
VD - decrease BP, prevent thrombosis
Rate-limiting - verapamil - most effects on heart
DHPs - amlodipine - target arteriolar smooth muscle (favoured) - prolong activation of cAMP
b-blocker
eg. atenolol - b1 -selective
eg. propranolol - b-nonselective
reduction in sympathetic drive to heart - decreases CO
a-blocker
last choice
VD, decrease BP
competitive receptor antagonist on a1-adrenoceptors on vascular smooth muscle
wide spread - many side effects
Digoxin
positive inotrope by inhibiting Na+/K+ ATPase
Na+ accumulates in myocytes, exchanged with Ca2+ leading to increased contractility
slows HR - improves cardiac filling
