Aminosalicylate drugs

Aminosalicylate drugs

5-aminosalicyclic acid (5-ASA) is released in the colon and is not absorbed. It acts locally as an anti-inflammatory. The mechanism of action is not fully understood but 5-ASA may inhibit prostaglandin synthesis

Sulphasalazine

• a combination of sulphapyridine (a sulphonamide) and 5-ASA
• many side-effects are due to the sulphapyridine moiety: rashes
  Sulphasalazine may cause Steven-Johnson syndrome
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  Importance: 10
  , oligospermia
  Sulphasalazine can cause oligospermia and infertility in men
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  Importance: 58
  , headache
  Sulphasalazine may cause headache
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  Importance: 12
  , Heinz body anaemia
  Sulphasalazine may cause Heinz body anaemia
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  Importance: 6
  , megaloblastic anaemia
  Megaloblastic anaemia is an adverse effect of sulphasalazine
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  Importance: 11
  , lung fibrosis
  Sulphasalazine may cause pulmonary fibrosis
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  Importance: 22
• other side-effects are common to 5-ASA drugs (see mesalazine)

Mesalazine

• a delayed release form of 5-ASA
• sulphapyridine side-effects seen in patients taking sulphasalazine are avoided
• mesalazine is still however associated with side-effects such as GI upset, headache, agranulocytosis, pancreatitis
  pancreatitis
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  *, interstitial nephritis

Olsalazine

• two molecules of 5-ASA linked by a diazo bond, which is broken by colonic bacteria

Aminosalicylates are associated with a variety of haematological adverse effects, including agranulocytosis

haematological adverse effects, including agranulocytosis

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- FBC is a key investigation in an unwell patient taking them.

*pancreatitis is 7 times more common in patients taking mesalazine than sulfasalazine

+PassMedicine Notes

5-aminosalicyclic acid (5-ASA) is released in the colon and is not absorbed. It acts locally as an anti-inflammatory. The mechanism of action is not fully understood but 5-ASA may inhibit prostaglandin synthesis

Sulphasalazine

• a combination of sulphapyridine (a sulphonamide) and 5-ASA
• many side-effects are due to the sulphapyridine moiety: rashes, oligospermia, headache, Heinz body anaemia, megaloblastic anaemia, lung fibrosis
• other side-effects are common to 5-ASA drugs (see mesalazine)

Mesalazine

• a delayed release form of 5-ASA
• sulphapyridine side-effects seen in patients taking sulphasalazine are avoided
• mesalazine is still however associated with side-effects such as GI upset, headache, agranulocytosis, pancreatitis*, interstitial nephritis

Olsalazine

• two molecules of 5-ASA linked by a diazo bond, which is broken by colonic bacteria

Aminosalicylates are associated with a variety of haematological adverse effects, including agranulocytosis - FBC is a key investigation in an unwell patient taking them.

*pancreatitis is 7 times more common in patients taking mesalazine than sulfasalazine