Which of the following drugs is NOT known to cause folate deficiency?

Pethidine, also known as meperidine, is an opioid analgesic that is primarily used for its pain-relieving properties. It does not interfere with folate metabolism or absorption in the body. In contrast, the other options have well-documented mechanisms or clinical effects that lead to folate deficiency.

5-Fluorouracil (5-FU) is an antimetabolite used in chemotherapy that inhibits thymidylate synthase, a crucial enzyme in the synthesis of thymidine, which is necessary for DNA synthesis. This action can disrupt rapidly dividing cells, including those that synthesize new DNA, contributing to a folate deficiency.

Methotrexate (MTX) is another chemotherapeutic agent that works as a folate antagonist. It competitively inhibits dihydrofolate reductase, an enzyme that plays a crucial role in the conversion of folate to its active form, thus limiting the availability of folate necessary for DNA synthesis and repair.

Ethanol (EtOH) can lead to folate deficiency through several mechanisms, including impaired absorption in the gastrointestinal tract and altered metabolism in the liver, which affects the conversion of folate to its active forms.

In summary, since pethidine does not