Indications: severe, active and progressive rheumatoid arthritis in patients not previously treated with methotrexate; psoriasis.

Cautions: predisposition to infection; significant exposure to herpes zoster virus—interrupt treatment and consider varicella–zoster immunoglobulin; heart failure (risk of exacerbation); demyelinating CNS disorders (risk of exacerbation); history of blood disorders; Tuberculosis Contra-indications: pregnancy; breast-feeding; active infection.

Side Effects: vomiting, oesophagitis, cholecystitis, pancreatitis, gastro-intestinal haemorrhage, myocardial or cerebral ischaemia, venous thromboembolism, hypotension, hypertension, dyspnea, demyelinating disorders, seizures, bone fracture, renal impairment, polymyositis, bursitis, lymphadenopathy.

Dose: By subcutaneous injection, rheumatoid arthritis, adult over 18 years, 25mg twice weekly or 50mg once weekly.

Psoriatic arthritis, ankylosing spondylitis, adult over 18 years, 25mg twice weekly.

Polyarticular-course juvenile idiopathic arthritis, child and adolescent 4–17 years, 400 mcg/kg twice weekly (max. 25mg twice weekly)

Psoriasis, adult over 18 years, initially 25–50mg twice weekly for up to 12 weeks then reduce to 25mg twice weekly; max. treatment duration 24 weeks; discontinue if no response after 12 weeks.