Treatment of Juvenile Rheumatoid Arthritis with Diclofenac Sodium

Diclofenac sodium was investigated in the treatment of juvenile rheumatoid arthritis (JRA). The pharmacokinetics of diclofenac in children aged 2-7 was assessed. Seven patients were included in a single-dose trial to determine plasma levels and renal elimination of diclofenac sodium. Venous blood samples were taken at 0, 0.5, 1, 2, 4 and 6 hours after administration of a 25 mg enteric-coated Voltaren® tablet. Urine was collected before and 0-6 and 6-12 hours after tablet ingestion. Maximum concentrations ranged from 0.79 to 4.25 μg/ml, and were found between 0.5 and 2 hours. Renal elimination of total diclofenac ranged from 5.4 to 10.2 % of the oral dose in 6 of the 7 patients. The youngest patient (2 years) had a lower elimination rate (2.25%) during the 12 hours observed. The values for children over 2 years corresponded to the range measured in adults. The pharmacokinetic study was followed by a placebo-controlled study with diclofenac sodium and acetylsalicylic acid (ASA) for 2 weeks in 45 hospitalized patients aged 3-15 years. The patients were randomly assigned to either: DS 2-3 mg/kg/day, microcrystallized ASA 50-100 mg/kg/ day, or placebo matching diclofenac. Global evaluation of therapeutic efficacy showed improvement in 73% of the patients in the diclofenac group, in 50 % of the ASA group and in 27 % of the placebo group. A statistically significant difference between these groups was found (p