Administration
Sulfasalazine conventional and delayed-release tablets are administered orally. The total daily dosage should be divided into equally divided doses, and, if possible, doses should be administered after meals. The delayed-release tablets should be swallowed whole.
Dosage
Ulcerative Colitis
For the treatment of ulcerative colitis, the interval between doses of sulfasalazine given as conventional or delayed-release tablets should not exceed 8 hours. The response to sulfasalazine in ulcerative colitis patients can be evaluated by clinical criteria (e.g., presence of fever, weight changes, degree and frequency of diarrhea and bleeding) as well as by sigmoidoscopy and evaluation of biopsy samples.
Continuation of sulfasalazine therapy may be necessary even when clinical symptoms, including diarrhea, have been controlled. When endoscopic examination confirms satisfactory improvement, sulfasalazine dosage may be decreased to a maintenance dosage.
If diarrhea recurs, dosage should be increased to previously effective dosage. Patients with ulcerative colitis should be advised that the disease rarely remits completely, and that continued use of maintenance dosages of sulfasalazine may decrease the risk of relapse.
The usual initial adult dosage of sulfasalazine given as conventional or delayed-release tablets for the treatment of ulcerative colitis is 3-4 g daily given in equally divided doses. In some patients, it may be advantageous to initiate therapy with a dosage of 1-2 g daily to lessen adverse GI effects. Although dosage as high as 12 g daily has been given, dosage exceeding 4 g daily is accompanied by increased incidence of adverse effects.
Some clinicians recommend that dosage exceeding 4 g daily be avoided unless the serum concentration of total sulfapyridine and the phenotype of the patient are known. The usual adult maintenance dosage is 2 g daily in 4 divided doses, although some clinicians advocate a lower maintenance dosage of 1-1.5 g daily if necessary to prevent adverse effects. The efficacy of maintenance therapy appears to be dose related, but the potential value of dosages greater than 2 g daily must be weighed against the risks of increased adverse effects and the necessity for more careful monitoring of the patient.
When sulfasalazine is given as conventional tablets for the treatment of ulcerative colitis in children 2 years of age or older, the usual initial dosage is 40-60 mg/kg daily in 3-6 divided doses and the usual maintenance dosage is 30 mg/kg daily in 4 divided doses. When sulfasalazine is given as delayed-release tablets for the treatment of ulcerative colitis in children 6 years of age or older, the usual initial dosage is 40-60 mg/kg daily in 3-6 divided doses and the usual maintenance dosage is 30 mg/kg daily in 4 divided doses.
Rheumatoid Arthritis in Adults
For the treatment of rheumatoid arthritis, the interval between doses of sulfasalazine given as delayed-release tablets usually is 12 hours. The usual adult dosage of sulfasalazine given as delayed-release tablets for the management of rheumatoid arthritis is 2-3 g daily given in equally divided doses.It may be advantageous to initiate therapy with a dosage of 0.5-1 g daily to lessen adverse GI effects.
The manufacturer recommends that patients receive 0.5 g every evening the first week of therapy, 0.5 g twice daily (morning and evening) the second week, 0.5 g every morning and 1 g every evening the third week, and 1 g twice daily (morning and evening) thereafter. A response to sulfasalazine (manifested by improvement in the number and extent of actively inflamed joints) may not occur until after 4-12 weeks of therapy. Patients receiving sulfasalazine dosages exceeding 2 g daily should be carefully monitored.
Juvenile Arthritis
The usual dosage of sulfasalazine given as delayed-release tablets for the management of polyarticular course juvenile rheumatoid arthritis in children 6 years of age and older is 30-50 mg/kg daily in 2 equally divided doses; the maximum dosage usually is 2 g daily. To reduce GI intolerance, the manufacturer recommends that sulfasalazine therapy in children be initiated with 1/4 to 1/3 of the planned maintenance dosage, and that dosage be increased at weekly intervals until the planned maintenance dosage is achieved (usually at week 4).