Indications: severe active or progressive rheumatoid arthritis, Still's disease; Wilson's disease; copper and lead poisoning.

Cautions: patients should be warned not to expect improvement for at least 6 to 12 weeks after initiation of treatment. Blood counts, including platelets, and urine examinations should be carried out every 1 or 2 weeks for the first 2 months then every 4 weeks to detect blood disorders and proteinuria. A reduction in platelet count indicates that treatment must be stopped and later re-introduced at a lower dosage level and then increased gradually, if possible; renal impairment; pregnancy and portal hypertension; avoid concurrent gold, chloroquine, hydroxychloroquine or immunosuppressive treatment.

Contra-indications: lupus erythematosus; moderate to severe renal impairment.

Side Effects: hypersensitivity reactions (may necessitate discontinuation of treatment), nausea, anorexia, taste loss, mouth ulcers, muscle weakness, skin reactions, oedema, proteinuria, agranulocytosis or severe thrombocytopenia which could be fatal; rarely myasthenia gravis, febrile reactions, lupus erythematosus.

Dose: rheumatoid arthritis, administered on expert advice, adults initial dose of 125-250mg daily before food for 1 month increased by this amount every 4 to 12 weeks until remission occurs.

Usual maintenance dose, 500-750mg daily but up to 1.5 g may rarely be given.

If remission has been sustained for 6 months, reduction of dosage by 125-250mg every 12 weeks may be attempted. Child, initial dose, 50mg daily before food for 1 month, increased at 4 weeks intervals to a maintenance dose of 15-20mg/kg daily.

Toxic metal poisoning (lead and copper), 1-2 g daily in divided doses before food until urinary lead is stabilized at less than 500mcg/day.

Child 20mg/kg daily.