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Clinical Trials

Colazal (balsalazide disodium)

The following drug information is obtained from various newswires, published medical journal articles, and medical conference presentations.

Approval Status:

Approved July 2000

Specific Treatments:

Mild to moderately active ulcerative colitis

General Information

Colazol is a 750mg balsalazide disodium capsule. Balsalazide disodium is cleaved enzymatically in the colon to produce mesalamine (5-aminosalicyclic acid) which has antiinflammatory properties.

Clinical Results

Two randomized, double-blind studies have been conducted using Colazol to determine its effectiveness in treating mild to moderate ulcerative colitis. The first study consisted of 103 subjects with active ulcerative colitis who showed evidence of spontaneously bleeding mucosa of the colon. These subjects were randomized and treated with either 6.75 grams/day of balsalazide or 2.25 grams/day. The efficacy endpoint of the trial was reduction in rectal bleeding, pain, stool frequency and other assessed symptoms. The study showed a statistically significant difference in efficacy between the high and low dose test groups.

The second study was conducted in Europe and showed similar findings.

Side Effects

Common side effect reported included, but were not limited to:

  • headaches
  • nausea
  • abdominal pain
  • diarrhea
  • vomiting
  • repiratory infection

Withdrawal from therapy due to these adverse effects were similar for patients using both drug and placebo.

Colazol is contraindicated for:

  • patients with a hypersensitivity to salicylates

Of the 259 patients treated with the 6.75 grams/day dose of Colazol, 3 reported exacerbated colitis, possibly due to use of the drug. (From FDA Label)

Caution should be used when proscribing Colazol to patients with known renal disorders or a history of renal failure.

No conclusive studies have been done on drug interactions with Colazol, though the use of antibiotics could possible weaken the effectiveness of the drug.

No reproduction studies have ever been done on humans, though studies on rats and rabbits have found that Colazol causes no harm to the fertility or fetus of these animals. It is not known whether or not the drug is secreted in the breast milk of nursing mothers.

Mechanism of Action

Balsalazide disodium is delivered intact to the colon where it is cleaved by bacterial azoreduction to release equimolar quantities of mesalamine, which is the therapeutically active portion of the molecule, and 4-aminobenzoyl-B-alanine. The recommended dose of 6.75 grams/day, for the treatment of active disease, provides 2.4 grams of free 5-aminosalicyclic acid to the colon.

The 4-aminobenzoyl-B-alanine carrier moiety released when balsalazide disodium is cleaved is only minimally absorbed and largely inert. The mechanism of action of 5-aminosalicyclic acid is unknown, but appears to be topical rather than systemic. Mucosal production of arachidonic acid metabolites, both through the cyclooxygenase pathways, ie. prostenoids, and through the lipoxygenase pathways, ie. leukotrienes and hydroxyeicosatetraenoic acids, is increased in patients with chronic inflammatory bowel disease, and it is possible that 5-aminosalicyclic acid diminishes inflammation by blocking production of arachidonic acid metabolites in the colon. (From FDA Label)

Additional Information

To find out more about ulcerative colitis and inflammatory bowel disease go to: Salix Pharmaceuticals - Inflammatory Bowel Disease

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