This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
[{'content': 'Which anti-glaucoma drug can be used in an asthmatic patient? \nSelect and explain. \nA. Timolol, B. Betaxolol, C. Propanolol, D. All', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ref: KD Tripathi pharmacology 6th edition (page.no: 144) Betaxolol is b1 selective blocker offering the advantage of less bronchopulmonary and probably less cardiac, central and metabolic side effects. In addition, it may exe a protective effect on retinal neurones independent of I.O.T lowering, possibly by reducing Na+ /Ca+ influx. Propanolol and Timolol are-selective b blockerS(b1 &b2). So b2 blocking effect precipitate asthma', 'role': 'assistant'}]