This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
[{'content': 'A patient of glaucoma with bronchial asthma presents to the emergency with status asthamaticus, causative agent might have. been \nSelect and explain. \nA. Pilocarpine eye drop, B. Timolol eye drop, C. Betaxolol eye drop, D. Levobunolol eye drop', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Timolol eye drop B2 receptors are responsible for bronchodialation, therefore blocking B2 would aggravate asthma and Timolol is nonselective beta blocker (i.e. blocks B1 & B2 both) Topical nonselective 0 blockers (e.g. timolol) are contraindicated in asthma Q, COPD, CHF, sinus bradycardia & AV blocks where as selective pi blockers (e.g. betaxolol) are C/I in sinus bradycardia & atrioventricular blocks only.', 'role': 'assistant'}]