Source: Pharmaceutical Benefits Scheme (AU) Revision Year: 2022 Publisher: Viatris Pty Ltd, Level 1, 30 The Bond, 30-34 Hickson Road, Millers Point NSW 2000, www.viatris.com.au, Phone: 1800 274 276
Mesalazine has been identified as the active component of sulfasalazine in inflammatory bowel disease and is thought to have a topical action.
In clinical studies, mesalazine has shown clinical efficacy similar to sulfasalazine.
The mode of the anti-inflammatory action of mesalazine is unknown. Inhibition of prostaglandin synthesis (via inhibition of cyclo-oxygenase), inhibition of chemotactic leukotriene synthesis (via inhibition of lipoxygenase), and direct inhibition of leukocyte motility may contribute to activity. More recent data suggest that the activity of mesalazine is based on a scavenging of oxygen free radicals, and that mesalazine is a biological antioxidant.
MESASAL enteric-coated tablets have an acrylic based resin coating which disintegrates when the surrounding pH is consistently above 6.4, permitting release of mesalazine in the terminal ileum and colon. The tablet coating is not affected by gastric contents or gastric residence time; but the presence of food tends to delay onward passage of the tablet.
Food may also delay the rate of absorption of mesalazine. In view of the probable topical action of mesalazine, however, this may not be therapeutically relevant.
Disintegration of the coating typically occurs about 5 hours after leaving the stomach. The simultaneous administration of agents which raise the gastric pH above 6.4, and the presence of achlorhydria, may decrease the time to release of mesalazine (see also Section 4.4 SPECIAL WARNINGS AND PRECAUTIONS FOR USE).
No data available
In fasted, healthy subjects given a single oral dose of mesalazine (500 mg), time to peak plasma concentration was 6.5 hours for mesalazine and 7 hours for acetyl-5-aminosalicylic acid (Ac-5-ASA). Urinary recovery was approximately 35%, and faecal recovery 26.5% of total dose.
Patients with Crohn’s Disease or Ulcerative Colitis
After oral administration of mesalazine 500mg t.i.d, the mean steady state plasma concentrations of 5-ASA and Ac-5-ASA averaged 0.7 and 1.2 μg/mL respectively.
After oral doses of mesalazine 250mg t.i.d, the mean steady state plasma concentration of 5-ASA and Ac-5-ASA averaged 0.4 and 1.0 μg/mL, respectively.
Peak concentrations of 5-ASA and Ac-5-ASA occurred at 4 to 6 hours after dosing.
Urine recovery data indicate that up to 44% of the dose is absorbed. Up to 35% of the dose remains unabsorbed and is excreted in the faeces.
About 80% of Ac-5-ASA is bound to plasma proteins.
Acetylation of mesalazine takes place in the liver and in the wall of the colon independently of acetylator status. The acetylation process appears to be saturable; however, at therapeutic doses (250-500 mg) neither maximum plasma concentration, nor area under the plasma concentration versus time curve for mesalazine indicated any deviation from dose linearity at steady state.
The mean elimination half-life of 5-ASA is 1.4 hours. Following oral administration, mesalazine is eliminated to a large extent as N-acetyl-5-aminosalicylic acid, both in the urine and the faeces. Following rectal administration, mesalazine is eliminated mainly as parent drug in the faeces. A poorer absorption of mesalazine from the distal colon has been suggested.
No data available.
No data available.
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