This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
True about tachyphylaxis is: 
Select and explain. 
A. Direct sympathomimetics involved, B. Mechanism clearly understood, C. Ephedrine tachyphylaxis reversed with dopamine, D. Indirect sympathomimetics involved
D: Indirect sympathomimetics involved
Answer: D: Indirect sympathomimetics involved 
Explanation: Tachyphylaxis refers to rapid development of tolerance when doses of a drug repeated in quick succession result in marked reduction in response . This is usually seen with indirectly acting drugs , such as ephedrine , Tyramine , nicotine. From medical pharmacology padmaja 4th edition page no 70