Anakinra is a specific receptor antagonist of interleukin-1 that differs from naturally occurring interleukin-1 receptor antagonist by the presence of a methionine group. It is administered by daily subcutaneous injection. Anakinra improves the clinical signs and symptoms of rheumatoid arthritis, slows radiographic progression and improves patient physical function. The most common adverse event is an injection site reaction. Anakinra has been associated with an increased incidence of serious infections and has an increased standardized incidence ratio for lymphoma. It has not been found to be associated with the development of opportunistic infections, worsening of congestive heart failure or the development of demyelinating disease. It appears to be effective in treating adult Stills disease, systemic-onset juvenile idiopathic arthritis and chronic infantile neurological cutaneous and articular syndrome (also known as neonatal-onset multisystem inflammatory disease syndrome).