NAPLEX (North American Pharmacist Licensure Examination) Practice Exam

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Which MS treatment is known as a pyrimidine synthesis inhibitor?

  1. Teriflunomide

  2. Fingolimod

  3. Natalizumab

  4. Dimethyl Fumarate

The correct answer is: Teriflunomide

Teriflunomide is known as a pyrimidine synthesis inhibitor. This medication works by inhibiting the enzyme dihydroorotate dehydrogenase, which is involved in the de novo pyrimidine synthesis pathway. By inhibiting this enzyme, teriflunomide reduces the proliferation of activated lymphocytes, which play a role in the pathophysiology of multiple sclerosis (MS). The other options listed are incorrect: - Fingolimod is a sphingosine-1-phosphate receptor modulator. - Natalizumab is an integrin receptor antagonist. - Dimethyl Fumarate is thought to have immunomodulatory properties, but its exact mechanism of action in treating MS is not fully understood.