Rheumatoid arthritis is an autoimmune disease that primarily affects the joints. It occurs when the immune system mistakenly attacks the synovium, which is the lining of the membranes that surround the joints. This leads to inflammation, pain, and stiffness in the affected joints.

The exact cause of rheumatoid arthritis is unknown. Several factors that contribute to its development:

1. Genetic factors: Certain genes may make individuals more susceptible to developing rheumatoid arthritis. However, not everyone with these genes will develop the disease, indicating that other factors also play a role.

2. Environmental factors: Environmental triggers such as viral or bacterial infections may activate the immune system and trigger an autoimmune response in susceptible individuals. Smoking is also considered a significant environmental risk factor for developing rheumatoid arthritis.

3. Hormones: The disease is more common in women, suggesting that hormonal factors may play a role. Some research suggests that hormonal changes during pregnancy may affect the immune system and contribute to the development or worsening of rheumatoid arthritis.

4. Age and gender: Rheumatoid arthritis can develop at any age, but it usually occurs between the ages of 40 and 60. 

5. Obesity: Being overweight or obese increases the risk of developing rheumatoid arthritis. Adipose tissue produces inflammatory chemicals that can contribute to joint inflammation.

It is important to note that while these factors are associated with an increased risk of developing rheumatoid arthritis, they do not guarantee the development of the disease. The interplay between genetic and environmental factors is complex, and researchers are still working to fully understand the underlying causes of rheumatoid arthritis. There are several medications available for the treatment of arthritis, including:

1. Nonsteroidal anti-inflammatory drugs (NSAIDs): These medications help relieve pain, reduce inflammation, and improve joint mobility. Examples include ibuprofen, naproxen, and celecoxib.

2. Disease-modifying antirheumatic drugs (DMARDs): These medications can slow the progression of arthritis and prevent further joint damage. Methotrexate, sulfasalazine, and leflunomide are commonly prescribed DMARDs.

3. Biologic response modifiers: These medications target specific components of the immune system to reduce inflammation and decrease joint damage. Examples include tumor necrosis factor inhibitors (etanercept, infliximab), interleukin-6 inhibitors (tocilizumab), and Janus kinase inhibitors (tofacitinib).

4. Corticosteroids: These medications are frequently used to reduce inflammation, swelling, and pain in affected joints. They are typically prescribed for short-term use due to potential side effects when used long-term.

5. Analgesics: These medications relieve pain but do not target the underlying inflammation. Examples include acetaminophen (paracetamol) and tramadol.

It is important to consult with a healthcare professional for an accurate diagnosis and to determine the most appropriate medication for individual circumstances.