Methotrexate (an older cancer treatment medication) can be used as first-line therapy for rheumatologic and psoriatic diseases. One of the side effects of methotrexate usage mimics which one of the following vitamin deficiencies?
Methotrexate targets and inhibits FH2 reductase, which catalyzes the reduction of FH2 to FH4 . Thus, in the presence of methotrexate, FH4 cannot be regenerated, and the body becomes functionally folate deficient. Methotrexate does not interfere with the absorption or reactions of the other B vitamins listed as potential answers.
Pyridoxine (B6)
Biotin (B7)
Niacin (B2)
Folate (B9)
Proteins and Amino Acids