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Olsalazine Dosage

Medically reviewed on December 15, 2017.

Applies to the following strengths: 250 mg

Usual Adult Dose for Ulcerative Colitis - Active

500 mg - 1 g orally per day, given in 2 equally divided dosages. Alternatively, doses of 500 mg up to 4 times a day have been used in severe cases.

Usual Adult Dose for Ulcerative Colitis - Maintenance

500 mg orally twice a day.

Usual Adult Dose for Ankylosing Spondylitis

Study (n=4)
500 mg 2 times daily for one week, increased by 500 mg weekly to a maximum of 1 g 3 times daily, for a total of 6 months.

Usual Pediatric Dose for Ulcerative Colitis

Study (n=56)
Greater than or equal to 2 years: 30 mg/kg/day (maximum, 2 g/day), starting at 25% of calculated daily dose, and increasing by one dose every third day, to four doses per day.

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available


Diarrhea has been reported during olsalazine therapy. The adverse event appears to be dose related, although it may be difficult to distinguish from the underlying symptoms of the disease.

Exacerbation of the symptoms of colitis thought to have been caused by mesalamine or sulfasalazine has been observed.

Monitoring of creatinine, blood urea nitrogen, and urinalysis is recommended in patients with preexisting renal disease because of the potential for renal tubular damage due to absorbed mesalamine or its n-acetylated metabolite. Although renal abnormalities were not observed in clinical trials with olsalazine, there have been rare reports from postmarketing experience.

Patients with impaired hepatic function should be monitored during therapy.

Urinary bladder transitional cell carcinomas have been found in animal studies receiving olsalazine 10 to 100 times the human maintenance dose.

Patients with severe allergies or asthma should be observed for signs of worsening symptoms.

In general, elderly patients should be treated with caution due to the greater frequency of decreased renal, hepatic, or cardiac function, co-existence of other disease, as well as concomitant drug therapy.

Safety and effectiveness in a pediatric patients have not been established.


Data not available

Other Comments

Olsalazine should be given with food. Active therapy for ulcerative colitis should be continued until remission, usually 2-4 months.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.