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 patient of bronchial asthma is on theophylline. Which of the following drugs should not be indicated to treat the upper respiratory tract infection in the same patient? \nSelect and explain. \nA. Ciprofloxacin, B. Amoxicillin, C. Ampicillin, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Drugs like ciprofloxacin,\xa0erythromycin and cimetidine are powerful microsomal enzyme inhibitors, predisposing to toxicity\xa0of theophylline.', 'role': 'assistant'}]