Which of the following is NOT categorized as a nonbiologic DMARD?

Infliximab is a biologic DMARD (Disease-Modifying Anti-Rheumatic Drug), making it the correct choice for the question regarding which option is NOT categorized as a nonbiologic DMARD. Biologic DMARDs are typically derived from living organisms and target specific components of the immune system, while nonbiologic DMARDs are synthetic or non-biologically derived medications that generally have a broader mechanism of action.

Hydroxychloroquine, leflunomide, and methotrexate are all classified as nonbiologic DMARDs. Hydroxychloroquine is primarily used for rheumatoid arthritis and lupus, leflunomide has immunomodulatory effects, and methotrexate is a well-established cornerstone in the management of various rheumatic diseases. Each of these drugs works by modulating the immune response and slowing disease progression, without the specific targeting found in biologic agents like infliximab, which targets the tumor necrosis factor (TNF) to reduce inflammation and immune response.