6467150
Description
Flashcards by Andrew Street, updated more than 1 year ago
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Created by Andrew Street
about 8 years ago
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| Question | Answer |
| Eg's of and indications for aminosalicylates. | eg's: mesalazine, sulfasalazine Indications: • Ulcerative colitis - mesalazine is 1st line Rx for mild-to-moderate cases • RA - sulfasalazine is a DMARD usually used as part of combination therapy |
| MOA of aminosalicylates. | In UC, mesalazine & sulfasalazine both exert their therapeutic effects by releasing 5-aminosalicylic acid (5-ASA). The precise mechanism of action of 5-ASA is unknown, but it has both anti-inflammatory & immunosuppressive effects, & 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. Sulfasalazine consists of a molecule of 5-ASA linked to sulfapyridine. In the colon, bacterial enzymes break this link and release the two molecules. Sulfapyridine does not contribute to its therapeutic effect in UC, but it does cause side effects, & for this reason it has largely been replaced by mesalazine for this indication. By contrast, sulfapyridine is probably active in rheumatoid arthritis, though its mechanism is unclear. Mesalazine has no role in rheumatoid arthritis. |
| SE's of aminosalicylates. | • GI upset • Headache • BD abnormalities - eg leucopenia, thrombocytopenia (both rare) • Renal impairment • Oligospermia • Serious hypersensitivity reaction |
| CI's, cautions, & important interactions of aminosalicylates. | CI's: • Aspirin hypersensitivity Cautions: • None Important interactions: Mesalazine tablets with a pH-sensitive coating (e.g. Asacol® MR) may interact with drugs that alter gut pH. For example, PPI's ^gastric pH so may cause the coating to be broken down prematurely. Lactulose lowers stool pH & may prevent 5-ASA release in the colon. |
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