Leflunomide is an alternative option for patients unresponsive or intolerant to methotrexate. However, experience with this drug in childhood arthritis is still scarce and the drug is not approved for JIA by regulatory authorities.
Children with a weight less than 20 kg receive 100 mg of leflunomide orally for one day, followed by a maintenance dose of 10 mg every other day. Children weighing 20 to 40 kg are given 100 mg of leflunomide for two days, followed by a maintenance dose of 10 mg per day. Children weighing more than 40 kg receive 100 mg of leflunomide for three days, followed by a maintenance dose of 20 mg per day.
Because leflunomide is teratogenic (can cause malformation to the fetus), young females of childbearing potential must have a negative pregnancy test before starting this medication and must adopt appropriate contraception.
Diarrhea, nausea, vomiting are the main side effects. In case of toxicity, treatment with cholestyramine under medical control is needed.
Juvenile idiopathic arthritis (the drug is not approved for use in juvenile idiopathic arthritis).