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: Pathology
All of the following cause macrocytic anaemia, except - 
Select and explain. 
A. Primaquine, B. Methotrexate, C. Trimethoprin, D. Azathioprine
A: Primaquine
Answer: A: Primaquine 
Explanation: Ans. is 'a' i.e., Primaquine Some impoant drugs causing megaloblastic anaemia o Methotrexate o Phenobarbitone o Zidovudine * o Triamterene o Trimethoprim o Phenytoin o Pentamidine o 5-Fluorouracil o Primidone o Azathioprine Cytosine arabinoside