NAPLEX (North American Pharmacist Licensure Examination) Practice Exam

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Ace your North American Pharmacist Licensure Examination (NAPLEX) with our comprehensive practice test. Features include interactive flashcards, multiple-choice questions, with detailed hints and explanations. Fast-track your pharmacy career today!

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Which Traditional DMARD is known to irreversibly bind and inhibit dihydrofolate reductase?

Leflunomide
MTX (Trexall)
Hydroxychloroquine
Sulfasalazine

The correct answer is: MTX (Trexall)

MTX, also known as methotrexate, is a Traditional DMARD that irreversibly binds and inhibits dihydrofolate reductase. This prevents the production of folic acid, which is necessary for cell division and growth. This action helps to suppress the immune system and reduce inflammation, making it an effective treatment for certain types of autoimmune diseases. Leflunomide (A), Hydroxychloroquine (C), and Sulfasalazine (D) are also Traditional DMARDs, but they do not irreversibly bind and inhibit dihydrofolate reductase. Instead, they work through different mechanisms to suppress the immune system and reduce inflammation. Leflunomide inhibits pyrimidine synthesis, Hydroxychloroquine disrupts antigen processing and presentation, and Sulfasalazine inhibits the production of pro-inflammatory cytokines. While these medications may also be useful in treating autoimmune diseases, they are not specifically known to bind to and inhibit dihydrofolate reductase.