Diclofenac Sodium Injection is a pain-relieving medication used to treat joint pain, swelling, and stiffness in conditions like rheumatoid arthritis, osteoarthritis, and acute musculoskeletal injuries. It is administered by a healthcare professional and should not be self-administered. Patients with a history of heart disease or stroke should consult their doctor for injection site reactions. Common side effects include nausea, limb discomfort, and injection site reactions. Long-term use may lead to serious complications like stomach bleeding and kidney problems.