Which drug blocks folic acid metabolism to cause early abortion?

Which drug blocks folic acid metabolism to cause early abortion?

• A. Leuprolide
• B. Zidovudine
• C. Methotrexate
• D. Mifepristone

Answer: (C)

Blocking folate metabolism to stop rapid cell division in early pregnancy is the idea behind using this drug for medical abortion. Methotrexate is a folate analog that inhibits dihydrofolate reductase, preventing formation of tetrahydrofolate and halting thymidylate and purine synthesis needed for DNA replication. This disrupts the rapid proliferation of placental tissue in early pregnancy, leading to termination, often used in combination with misoprostol to induce uterine contractions. The other drugs work by different mechanisms: one suppresses gonadotropin release to lower ovarian steroid production, another inhibits reverse transcriptase in HIV therapy, and the last blocks progesterone receptors to trigger decidual breakdown and abortion. Therefore, the drug that blocks folic acid metabolism to cause early abortion is methotrexate.

Blocking folate metabolism to stop rapid cell division in early pregnancy is the idea behind using this drug for medical abortion. Methotrexate is a folate analog that inhibits dihydrofolate reductase, preventing formation of tetrahydrofolate and halting thymidylate and purine synthesis needed for DNA replication. This disrupts the rapid proliferation of placental tissue in early pregnancy, leading to termination, often used in combination with misoprostol to induce uterine contractions. The other drugs work by different mechanisms: one suppresses gonadotropin release to lower ovarian steroid production, another inhibits reverse transcriptase in HIV therapy, and the last blocks progesterone receptors to trigger decidual breakdown and abortion. Therefore, the drug that blocks folic acid metabolism to cause early abortion is methotrexate.