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
Methotrexate is used in all except? 
Select and explain. 
A. Sickle cell anemia, B. Psoriasis, C. Rheumatoid ahritis, D. Ankylosing spondylitis
A: Sickle cell anemia
Answer: A: Sickle cell anemia 
Explanation: Ans. is 'a' i.e., Sickle cell anemia Uses of Methotrexate Methotrexate can be used in following conditions: i) Conditions which are associated with abnormally rapid cell growth.. Neoplasia (carcinoma of breast), Psoriasis. ii) Inflammatory conditions: RA, AS, lupus, Crohn:s disease. iii) Recently methotrexate has been shown to be effective in inducing miscarriage, e.g. in ectopic pregnancy. This effect of methotrexate is attributed to its action of killing rapidly growing cells of placenta.