1.) Medication to treat the main infection
Because reactive arthritis is an autoimmune reaction, antibiotics have not been shown to treat the arthritis, though they can help clear an infection. Often, NSAIDs are used as the first line, and if needed, a steroid or other immune suppressant.
Urinary Tract or Gastrointestinal System
If you have obvious signs of a bacterial infection in your urinary tract or gastrointestinal system, antibiotics can help it clear up. Which antibiotic you take will depend on what kind of bacterial infection you have. Your doctor may need to run tests to find out. Viral and fungal infections are harder to treat.