Reduced absorption of folic acid and digoxin have been reported when those agents were administered
concomitantly with sulfasalazine.
When daily doses of sulfasalazine 2 g and weekly doses of methotrexate 7.5 mg were coadministered to
15 rheumatoid arthritis patients in a drug-drug interaction study, the pharmacokinetic disposition of the drugs was
Daily doses of sulfasalazine 2 g (maximum 3 g) and weekly doses of methotrexate 7.5 mg (maximum 15 mg)
were administered alone or in combination to 310 rheumatoid arthritis patients in two controlled 52-week clinical
studies. The overall toxicity profile of the combination revealed an increased incidence of gastrointestinal adverse
events, especially nausea, when compared to the incidence associated with either drug administered alone.
Drug/Laboratory Test Interactions: The presence of sulfasalazine or its metabolites in
body fluids has not been reported to interfere with laboratory test procedures.
7.Farr M, et al. Immunodeficiencies associated with sulphasalazine therapy in inflammatory arthritis.
British Jnl Rheum 1991;30:413-417.