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: Pharmacology
[{'content': 'Which of the following is a long-acting beta 2 agonist \nSelect and explain. \nA. Orciprenaline, B. Penoterol, C. Pexbaterol, D. Salmeterol', 'role': 'user'}, {'content': 'Answer: D \nExplanation: β2-agonists used in Asthma.\n\nShort-acting → Salbutamol, terbutaline\nLong-acting → Salmeterol, formoterol\n\n\xa0Bambuterol is a prodrug of terbutaline.\nIt is slowly hydrolysed by pseudocholinesterase.\n\n\xa0Short-acting β2-agonists produce bronchodilation within 5 min and acting lasts for 2-6 hrs → are used to abort and terminate acute asthma,\xa0but are not suitable for prophylaxis.\n\xa0Salmeterol is delayed acting,\xa0can be used for prophylaxis only,\xa0while formoterol is fast acting and long acting can be used for both prophylaxis and acute attack.\n\nSalbutamol & Terbutaline → Only for acute attack. Salmeterol → Only for prophylaxis. Formoterol → Both for prophylaxis and acute attack\n\n\xa0Long-acting β2-agonists.\n\n(salmeterol & formoterol) are superior to short-acting β2-agonists (salbutamol & terbutaline),\xa0and equivalent to inhaled anticholinergics in COPD. Note: For one option go ahead with option ‘d’, i.e.,\xa0adrenaline because amongst the given options, adrenaline is the shortest acting (60 - 90 minutes).\n\n\xa0Salmeterol and formoterol are long-acting β2,-agonists.\n\xa0Their lipophilic action is responsible for longer action → Lipophilic side chain anchors the drug in membrane adjacent to the receptor, slowing issue washout.', 'role': 'assistant'}]