<prompt> A patient came to the casualty with acute attack of asthma after starting treatment of glaucoma. The causative drug isTimololBetaxololClonidineAcetazolamide  <response>: Ans. a TimololRef: Kanski 7e, p. 383; Katzung 12e, p. 158Timolol is a non-selective beta blocker and thus acts on Beta 2 receptors also, leading to broncospasm and exacerbation of asthmaBetaxolol is a cardioselective beta 1 blocker and thus is free from this side effect 