Chemical: Drug

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Generic Names
  • Olsalazine sodium
Trade Names
  • Dipentum
Brand Mixture Names

PharmGKB Accession Id





Olsalazine is an anti-inflammatory drug used in the treatment of Inflammatory Bowel Disease and Ulcerative Colitis. Olsalazine is a derivative of salicylic acid. Inactive by itself (it is a prodrug), it is converted by the bacteria in the colon to mesalamine. Mesalamine works as an anti-inflammatory agent in treating inflammatory diseases of the intestines.

Source: Drug Bank


For the treatment of Inflammatory Bowel Disease and Ulcerative Colitis.

Source: Drug Bank

Other Vocabularies

Information pulled from DrugBank has not been reviewed by PharmGKB.

Pharmacology, Interactions, and Contraindications

Mechanism of Action

Orally administered olsalazine is converted to mesalamine which is thought to be the therapeutically active agent in the treatment of ulcerative colitis. The mechanism of action of mesalamine (and sulfasalazine) is unknown, but appears to be topical rather than systemic. Mucosal production of arachidonic acid (AA) metabolites, both through the cyclooxygenase pathways, i.e., prostanoids, and through the lipoxygenase pathways, i.e., leukotrienes (LTs) and hydroxyelcosatetraenoic acids (HETEs) is increased in patients with chronic inflammatory bowel disease, and it is possible that mesalamine diminishes inflammation by blocking cyclooxygenase and inhibiting prostaglandin (PG) production in the colon.

Source: Drug Bank


Olsalazine is an anti-inflammatory drug used in the treatment of Inflammatory Bowel Disease and Ulcerative Colitis. Olsalazine reduces the bowel inflammation, diarrhea (stool frequency), rectal bleeding, and abdominal pain. Like Balsalazide, Olsalazine is believed to deliver Mesalazine, or 5-aminosalicylic acid (5-ASA), past the small intestine, directly to the large intestine, which is that active site of disease in ulcerative colitis.

Source: Drug Bank

Absorption, Distribution, Metabolism, Elimination & Toxicity


Most (98 to 99%) of an oral dose is rapidly converted into two molecules of 5-aminosalicylic acid (5-ASA) by colonic bacteria and the low prevailing redox potential found in this environment. The conversion of olsalazine to mesalamine in the colon is similar to that of sulfasalazine, which is converted into sulfapyridine and mesalamine. Approximately 0.1% of an oral dose of olsalazine is metabolized in the liver to olsalazine-O-sulfate (olsalazine-S)

Source: Drug Bank

Protein Binding

Olsalazine and olsalazine-S are more than 99% bound to plasma proteins. Mesalamine (5-ASA) is 74% bound to plasma proteins.

Source: Drug Bank


After oral administration, olsalazine, has limited systemic bioavailability. 98-99% of the dose is converted to mesalamine (5-ASA) in the colon, which is absorbed slowly resulting in very high local concentrations in the colon.

Source: Drug Bank


Olsalazine has an elimination half-life of 0.9 hours, however, olsalazine-S has a half-life of 7 days.

Source: Drug Bank


Maximum single oral doses of 5g/kg in mice and rats and 2 g/kg in dogs were not lethal.

Source: Drug Bank

Route of Elimination

Approximately 0.1% of an oral dose of olsalazine is metabolized in the liver to olsalazine-O-sulfate (olsalazine-S).The remaining 5-ASA is partially acetylated and is excreted in the feces.

Source: Drug Bank

Chemical Properties

Chemical Formula


Source: Drug Bank

Isomeric SMILES


Source: OpenEye

Canonical SMILES


Source: Drug Bank

Average Molecular Weight


Source: Drug Bank

Monoisotopic Molecular Weight


Source: Drug Bank



Source: Drug Bank

InChI String


Source: Drug Bank

Genes that are associated with this drug in PharmGKB's database based on (1) variant annotations, (2) literature review, (3) pathways or (4) information automatically retrieved from DrugBank, depending on the "evidence" and "source" listed below.

No related genes are available.

Drug Interactions

Interaction Description
thioguanine - olsalazine The 5-ASA derivative increases the toxicity of thiopurine (source: Drug Bank )
thioguanine - olsalazine The 5-ASA derivative increases the toxicity of thiopurine (source: Drug Bank )

Relationships from National Drug File - Reference Terminology (NDF-RT)

May Treat
Contraindicated With


Web Resource:
National Drug Code Directory:
KEGG Compound:
KEGG Drug:
PubChem Compound:
PubChem Substance:
Drugs Product Database (DPD):
FDA Drug Label at DailyMed:

Clinical Trials

These are trials that mention olsalazine and are related to either pharmacogenetics or pharmacogenomics.

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NURSA Datasets

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Sources for PharmGKB drug information: DrugBank, PubChem.