system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 7-year-old boy is brought to the physician by his mother because of a 2-week history of intermittent shortness of breath and a dry cough that is worse at night. He had an upper respiratory tract infection 3 weeks ago. Lungs are clear to auscultation. Spirometry shows normal forced vital capacity and peak expiratory flow rate. The physician administers a drug, after which repeat spirometry shows a reduced peak expiratory flow rate. Which of the following drugs was most likely administered?
assistant
Methacholine