Aminosalicylates

Question 1

Example of a Aminosalicylates

Answer 1

Mesalazine

Question 2

How does mesalazine work?

Answer 2

In ulcerative colitis (UC), mesalazine exerts its therapeutic effects by releasing 5-aminosalicylic acid. The mechanism is unknown, but it has both anti-inflammatory and immunosuppressive effects, and appears to act topically on the gut rather than systemically.

For this reason, 5-ASA preparations are designed to delay delivery of the active ingredient to the colon.

The oral form of mesalazine comprises a tablet with a coating that resists gastric breakdown, instead releasing 5-ASA further down the gut.

Sulfapyridine causes side effects and has been replaced by mesalazine. Sulfapyridine is active in rheumatoid arthritis; Mesalazine has no role in rheumatoid arthritis.

Question 3

Indications of mesalazine?

Answer 3

Ulcerative Colitis (first line)

Question 4

Contraindications of mesalazine?

Answer 4

Mesalazine is a salicylate, like aspirin. Patients who have aspirin hypersensitivity should not take these drugs.

Question 5

Side effects if mesalazine?

Answer 5

GI upset (e.g. nausea, dyspepsia) and headache.
It can also cause rare but serious blood abnormalities (e.g. leucopenia, thrombocytopenia) and renal impairment

Question 6

Possible interactions of mesalazine

Answer 6

Mesalazine tablets with a pH-sensitive coating (e.g. Asacol® MR) may interact with drugs that alter gut pH. For example, proton pump inhibitors increase gastric pH so may cause the coating to be broken down prematurely.

Question 7

Elimination of mesalazine

Answer 7

Renal

Question 8

Patient information for mesalazine

Answer 8

In an acute attack, this is taken once or twice daily for 4–6 weeks to induce remission. If the patient would prefer not to take the drug rectally, an oral formulation may be used.

Ask them to report any unexplained bleeding, bruising, or infective symptoms as this could be a sign of a blood count abnormality that may require urgent assessment

Ensure the patient understands how to take the medicine, particularly if it is a rectal preparation.