Phthalylsulphathiazole in rheumatoid arthritis

Sixteen patients with active rheumatoid arthritis were treated with phthalylsulphathiazole (4 g/day) over a period of 24 weeks. Although there was some statistically significant improvement in plasma viscosity, IgM, pain score, morning stiffness and summated change score, this was either intermittent or not maintained. Five patients withdrew from the trial before completion, four (25%) with non-serious adverse reactions and one patient from lack of efficacy; only one patient elected to remain on the drug beyond the 24-week period. Low free and total sulphathiazole serum concentrations were found, confirming that most of the drug remained within the gut. This investigation suggests, certainly at the dose used, that phthalylsulphathiazole does not have the properties of a second-line agent. Higher doses of the drug will not be ethically feasible.