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': 'OCP fails when used with the following drugs, EXCEPT: \nSelect and explain. \nA. Aspirin, B. Phenytoin, C. Rifampin, D. Tetracycline', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Larger doses of aspirin may be required when given with oral contraceptive pills. Drugs that May Reduce Combined Hormonal Contraceptive Efficacy: Antituberculous Rifampin Antifungals Griseofulvin Anticonvulsants and Sedatives Phenytoin Mephenytoin Phenobarbital Primidone Carbamazepine Ethosuximide Antibiotics Tetracycline Doxycycline Penicillins Ciprofloxacin Ofloxacin Antiretrovirals Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 32. Contraception. In F.G. Cunningham, K.J. Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e.', 'role': 'assistant'}]