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Aminosalicylates ( 5-ASA compounds )

AMINOSALICYLATES compounds that contain 5- aminosalicylic acid ( 5- ASA ) exact mechanism of action is not known but is thought that – they have an anti-inflammatory action due to 
○ modulation of inflammatory cytokine production
○ decreased transcriptional activity of nuclear factor-kappa B 
○ inhibition of the biosynthesis of prostaglandins and leukotrienes they are not immunosuppressant’s they act locally on the colon and are absorbed by colonic epithelial cells as they act locally within the lumen of the intestine achieving maximal conc of the agent at the site of the active disease is vital used in treatment of both UC and Crohn’s but thought to be more effective in UC indications for use of 5-ASA’s include
○ treatment of mild to moderate UC , acute flare up
○ maintenance of remission of UC
○ treatment of active CD
○ maintenance of remission of CD

PRODUCTS – availability of products may vary between regions newer 5-ASA’s include mesalazine , osalazine and balsalazide and they are better tolerated than sulfasalazine mesalamine ( Pentasa ) does not contain the sulfa group and about 90 % of patients who cannot tolerate sulfasalazine due to the sulfa group can tolerate mesalamine
mesalamine coating influences where the drug would be releases and how frequently should it be administered rectal preparations ( theoretically ideal as these agents work locally ) as gels , liquids and foam enemas are often associated with undesirable side effects as leakage , abdominal bloating ( leading to poor adherence ) for proctitis as liquid 5-ASA enema may be more appropriate as > 90 % of the enema bypasses the rectum Asacol foam is better tolerated than liquid enema whereas Salofalk enemas provide double the necessary dose a combination of enemas and suppositories may be used for distal disease formulations vary in their indications , dosing , frequency of use , interactions , pharmaceutical , pharmacological and pharmacokinetic properties.


Azo bond formulations – Sulfasalazine ( Azulfidine ) contains mesalazine and sulfapyridine molecule bound by an azo bond which is cleaved upon exposure to colonic bacteria Osalazine ( Dipentum ) Balsalazide ( Colazal )


Mesalamine preparations – Mesalamine ( Asacol ) Mesalamine ( Pentasa ) Pentasa available as tablets , granules , enemas and suppositories site of action is from duodenum to rectum. Octasa – available as tablets and site of action is terminal ileum and colon Salofalk available as tablets , granules M/R , enema and foam enemas ( site of action is terminal ileum and colon Asacol , Asacol MR as tablets and suppositories , site of action is terminal ileum and large bowel 
( colon & rectum ).


Side effects
 mesalazine is generally well tolerated with similar SE profile between various formulations all 5- ASA agents may cause headache , nausea , abdominal pain and cramping , arthralgia , myalgia ,loss of appetite , vomiting , rash fever , diarrhoea they should be avoided in those with kidney problems and those who are taking it kidney tests should be done routinely rare and serious SEs include interstitial nephritis and pancreatitis.


  1. Mesalazine and other aminosalicylates in Inflammatory Bowel Disease ( Adults ) mesalazine and other aminosalicylates in inflammatory bowel disease (
  2. Fact Sheet News from the IBD help center Crohn’s and Colitis Foundation aminosalicylates.pdf (
  3. 5-ASA’s in the Treatment of Inflammatory Bowel Disease Brian Bosworh MD and Ellen J Scherl MD Gastroenterology and Endoscopy News  July 2011 untitled (
  4. Ye, Bei, and Daniel R van Langenberg. “Mesalazine preparations for the treatment of ulcerative colitis: Are all created equal?.” World journal of gastrointestinal pharmacology and therapeutics vol. 6,4 (2015): 137-44. doi:10.4292/wjgpt.v6.i4.137


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