Medicine A young man with leukemia is treated with methotrexate. Which of the following is the mechanism of action of this drug? A preventing absorption of folic acid B inhibiting dihydrofolate reductase C preventing formation of messenger ribonucleic acid (mRNA) D forming a cytotoxic metabolite 💡 Explanation A young man with leukemia is treated with methotrexate. Which of the following is the mechanism of action of this drug? ✓ Correct Answer: B. inhibiting dihydrofolate reductase