Also known by its brand name “Arcalyst”, Rilonacept is indicated for the treatment of “some of the symptoms of rare genetic conditions such as Familial Cold Auto-inflammatory Syndrome or Muckle-Wells Syndrome”. (drugs.com) According to the same source, these two conditions are “inflammatory disorders in which the body develops certain symptoms (such as fever, chills, fatigue, and joint pain) without a known cause (such as virus, bacteria, or illness)”. There are also other symptoms that are more serious, considering they may affect bones and joints, the central nervous system, or major organs such as the kidneys. Even though the medication in question may treat or even prevent these symptoms, it will not cure the genetic conditions that cause them. When it comes to the common side effects of Rilonacept, they include numbness, nausea, and flu symptoms. There are also other side effects that require immediate medical care such as signs of infection (flu symptoms, mouth sores, and unusual weakness), trouble breathing, painful urination, neck stiffness, and increased sensitivity to light. It is actually not known whether Rilonacept is safe during pregnancy/breastfeeding. Therefore, you should consult your doctor before taking it.