What is olsalazine, and how does it work (mechanism of action)?

  • Olsalazine is an oral medication that works as an anti-inflammatory drug for treating inflammatory diseases of the colon. It is a derivative of salicylic acid. Inactive itself, it is converted by the bacteria in the colon to its active form, mesalamine. Following oral administration very little of the olsalazine (less than 10%) is absorbed from the intestine into the body. The benefit of mesalamine is believed to be due to a local effect from within the colon. Mesalamine also is thought to be the active component of another drug used for treating inflammatory diseases of the intestines, sulfasalazine (Azulfidine).
  • Olsalazine was approved by the FDA in July 1990.
  • The brand name for olsalazine is Dipentum.
  • Olsalazine is not available in generic form. You need a prescription to obtain this drug.

What is olsalazine used for?

Olsalazine is used to treat a digestive condition called ulcerative colitis or UC.

What are the side effects of olsalazine?

Common side effects are:

Other important side effects include:

Gastrointestinal disturbances commonly occur in persons who take olsalazine. Diarrhea occurs in about 1 of every 6 persons who take it; about one in 20 need to discontinue therapy because the diarrhea is severe. Abdominal pain or cramps occur in 1 in 10 persons, and nausea or vomiting occurs in 1 in 20. Other side effects, including dizziness, depression, and headache, occur less frequently than gastrointestinal effects during therapy. Rashes occur in 2.3% of persons and joint pain in 4%.


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What is the dosage for olsalazine?

Olsalazine usually is administered at a dose of 500 mg (two capsules) twice daily. It should be taken with meals.

Is olsalazine safe to take if you are pregnant or breastfeeding?

Mesalamine, which is the active form of olsalazine, may be secreted into breast milk and cause diarrhea in the infant.

What else should you know about olsalazine?

What preparations of olsalazine are available?

Capsules: 250 mg.

How should I keep olsalazine stored?

The capsules should be kept at room temperature, 15 C to 30 C (59 F to 86 F).


Olsalazine (Dipentum) is an oral medication prescribed for maintaining remission of ulcerative colitis who do not tolerate sulfasalazine (Azulfidine). Side effects, drug interactions, and pregnancy safety information should be reviewed prior to taking this drug.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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FDA Prescribing Information.