Hydroxychloroquine 200 Mg Tab is primarily used to treat and prevent malaria. It is also prescribed for autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus (SLE) due to its anti-inflammatory and immunomodulatory effects. The medication helps reduce symptoms like pain, swelling, and joint stiffness in arthritis and manages skin and systemic manifestations in lupus. Always take hydroxychloroquine as prescribed by your healthcare provider, and be aware of potential side effects such as gastrointestinal disturbances, vision changes, and, in rare cases, serious eye problems. Regular monitoring by a healthcare provider is recommended during long-term use.