All of the following drugs useful in the treatment of a patient with acute bronchial asthma except:
(AIIMS Nov 2010)
Management of chronic asthma
1). Beta 2'"adrenoceptor agonists relax bronchial smooth muscle (cAMP), acting within minutes.
a. Salbutamol is best given by inhalation (aerosol, nebulizer), but may also be given per oral or IV.
b. Side Effect:
ii. Hypokalemia Q,
iv. Anxiety Q,
c. Long. Acting inhaled beta 2-agonist (eg salmeterol. formoterol) can help nocturnal symptoms and reduce morning dips.
d. They may be an alternative to steroid dose when symptoms are uncontrolled. Salmeterol are not given in acute attack
Side Effect: as salbutamol. Paradoxical bronchospasm Q (salmeterol). Tolerance and arrhythmias can occur.
2). Corticosteroids are best inhaled to minimize systemic effects, eg beclomethasone via spacer (or powder), but may be given PO or IV. They act over days to reduce bronchial mucosal inflammation.
Extra Edge: Asthma is characterized by hyperresponsiveness of airways
1). Asthma is an allergic disease of the airways
2). Inhaled corticosteroids are the mainstay of treatment
3). Aminophylline (metabolized to theophylline) may act by inhibiting phosphodiesterase, thus reduce bronchoconstriction by increasing cAMP levels.
4). Anticholinergics (eg ipratropium, tiotropium) may reduce muscle spasm synergistically with beta 2-agonists.
5). Cromoglycate May be used as prophylaxis Q in mild and exercise-inducedQ asthma (always inhaled), especially in children.
6). Leukotriene receptor antagonists (eg montelukast, zafirlukast Q) block the effect of cysteinyl leukotrienes in the airways. Not effective in acute attack.
Step-wise approach to asthma therapy according to the severity of asthma and ability to control symptoms. ICS, inhaled corticosteroid; LABA, long-acting Beta2-agonists; OCS, oral corticosteroid. (Ref. Hari-18th ed., fig.254.7, Pg 2113)