Which drug is not used for acute bronchial asthma ?

Ans. is 'a' i.e., Salmeterol Bambuterol is a prodrug of terbutaline. It is slowly hydrolysed by pseudocholineterase. Sho acting 132-agonists produce bronchodilatation within 5 min and action lasts for 2-6 hrs --> are used to abo and terminate acute asthma, but are not suitable for prophylaxis. Salmeterol is delayed acting, can be used for prophylaxis only, while formoterol is fast acting and long acting can be used for both prophylaxis and acute attack.