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': 'A 55–year–old female who is taking propranolol for the management of a cardiovascular disease experiences an acute asthmatic attack. Which of the following drugs would you prescribe to attenuate this asthmatic attack \nSelect and explain. \nA. Cromolyn sodium, B. Salbutamol, C. Beclomethasone, D. Ipratropium bromide', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Inhaled β2 agonists are the agents of choice for termination of acute attack of bronchial asthma. However, as the patient is receiving β-blockers, treatment with β2 agonists will be ineffective (receptors are already blocked). Therefore, other bronchodilators like anticholinergic agents (ipratropium) or methylxanthines (theophylline) will be useful in such a case.', 'role': 'assistant'}]