Asthma pharmacology Flashcards
B2 adrenoceptor agonists
short acting: salbutamol, terbutaline
long acting: formeterol, salmeterol
sm muscle relaxation, reduce inflamm mediators, reduce vascular permeability (muscosal oedema)
B2 agonist side effects
tachys and palpitations, pulmonary vasodilatation
Mechanism of action - B2 adrenoceptors
inc cAMP activate K+ channel activate Na+/K+ ATPase reduce Ca2+ actin and myosin coupling reduce para cholinergic neurotransmission
non selective B2 adrenoceptor agonists
isoprenaline/adrenaline injection for status asthmatics
inhibit type IV PDE – inc cAMP/cGMP — smooth muscle relaxation
antagonise adenosine receptor
stimulate CVS/resp centres
xanthine bronchodilators e.g. theophylline (oral), aminophylline (i.v.)
adjunct to steroids in B2 agonist unresponsiveness/ acute severe asthma
side effects of xanthines
CNS: insomnia, nervousness, seizures
CVS: palpitations, tachys, dysrrythmias
metabolism of xanthines
p450 enzymes in liver
reduce theophylline action by inc enzyme - carbemazepine
inc action, reduce enzyme - clarithromycin (CHEST INFECTION)
muscarinic (M3) antagonists - M3 = cholinergic stimulation –> contraction and secretion
ipratropium bromide (atrovent) - short acting
inhibit mucus
ineffective in late phase
tiotropium
long acting
COPD
zilutin
cysteinyl leukotriene antagonist
nausea, sleeplessness, flu, cough, reduce liver function
WITHDRAWN
cysteinyl leukotriene antagonist - block CysLT1 receptors for exercise induced asthma
montelukast
side effects: GI, headache
adjunct to salbutamol? less effective
glucocorticoid with less systemic effects
fluticasone
anti inflamm effects of glucocorticoids
reduce IL3 (mast cell) reduce IL5 (eosinophils)
prednisolone/prednisone
systemic oral glucocorticoid
hydrocortisone
iv systemic glucocorticoid for acute severe asthma
cromoglicate/nedocromil
prophylactic against int/late phase
reduce H release from mast cells
