Possible Interaction: Sulfasalazine and Folate

“The mechanisms by which sulphasalazine antagonizes folate metabolism are dose-dependent and, consequently, higher doses might precipitate folate deficiency.”

“Furthermore, sulfasalazine was found to be a potent inhibitor of PCFT, suggesting that it is a risk factor that would cause malabsorption of folate and also MTX, when coadministered in the treatment of rheumatoid arthritis.”

“Oral folic acid tolerance tests confirmed the observation that Azulfidine impaired intestinal folate absorption.”

“Although aminosalicylates can be continued, women taking sulfasalazine should increase their folate supplementation to 2 mg daily.”

“Patients with ulcerative colitis commonly have decreased folate levels, which are partially due to sulfasalazine , a competitive inhibitor of folate absorption.”

“Patients with ulcerative colitis commonly have decreased folate levels, which are partially due to sulfasalazine , a competitive inhibitor of folate absorption.”

“Pending a larger case-control study, folate supplementation during sulfasalazine administration is recommended to possibly prevent the complication of dysplasia or cancer in ulcerative colitis.”

“The mechanism appears to be acute folate deficiency, and the requirement for folinic acid in one case suggests that the known inhibition of folate metabolism by sulphasalazine also contributes.”

“Patients taking 2 g or more of sulfasalazine daily had lower mean RBC folate levels (221.2 +/- 27.3 ng/mL) than patients either taking less (371.7 +/- 35.0 ng/mL) or nonusers (330.3 +/- 30.3 ng/mL).”

“To the Editor.— The findings that sulfasalazine inhibits folate transport,1inhibits the hydrolysis of polyglutamyl folate, and decreases the absorption of both polyglutamyl and monoglutamyl folates suggest, as recently reported by Halstead et al,2that folate deficiency may be prevented by increasing folate intake while the patient receives sulfasalazine.”

“Although sulfasalazine inhibits folate absorption, anemia caused by folate deficiency is not common in patients with ulcerative colitis and adequate dietary intake of folate.”