Mesalamine
Synonyms :
5-aminosalicylic acid, 5-ASA, Mesalazine
Mechanism :
The mechanism of action of mesalamine is not fully understood but appears to be topical. Mucosal production of arachidonic acid metabolites, both through the cyclooxygenase and lipoxygenase pathways, is increased in patients with chronic inflammatory bowel disease, and it is possible that mesalamine diminishes inflammation by blocking cyclooxygenase and inhibiting prostaglandin production in the colon.
Indication :
- Ulcerative colitis (inflammatory bowel disease). Use suppositories and enemas particularly for distal disease.
- Maintenance of remission in Crohn’s disease
Contraindications :
Contraindicated in patients with hypersensitivity to salicylates or to any of the components, and in severe renal impairment. Serious blood dyscrasias have been reported very rarely with mesalazine. Contraindicated in severe hepatic impairment. Renal function should be regularly assessed, especially in children receiving large oral doses. In addition to routine blood counts and liver function tests, blood urea nitrogen and serum creatinine determinations and a urinalysis should be performed at least monthly for 3 months, then every 3-6 months.
Dosing :
>5 years of age:
17 to <33 kg: 36-71 mg/kg/day, orally in 2 divided doses. Max dose: 1.2 g/day.
33 to <54 kg: 37-61 mg/kg/day, orally in 2 divided doses. Max dose: 2 g/day.
54 to 90 kg: 27-44 mg/kg/day, orally in 2 divided doses. Max dose: 2.4 g/day.
Rectal doses only for children >12 years.
Adverse Effect :
Gastrointestinal: Abdominal pain, discomfort, flatulence, nausea, exacerbation of colitis.
Miscellaneous: Headache, fatigue, asthenia, malaise, weakness, fever, dizziness, rash, pruritus, acne.
Interaction :
Nephrotoxic agents, including non-steroidal anti-inflammatory drugs (NSAIDs): May increase the risk of renal reactions.
Azathioprine or 6-mercaptopurine: Concurrent use of mesalamine can increase the potential for blood disorders.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Caution – use only if necessary. Start with low dose and increase according to response |
| 10-20 | Caution – use only if necessary. Start with low dose and monitor closely |
| <10 | Caution – use only if necessary. Start with low dose and monitor closely |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Unlikely to be dialysed. Dose as in GFR<10 mL/min |
| HD | Unlikely to be dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Unknown dialysability. Dose as in GFR<10 mL/min |
| CAV/VVHD | Unknown dialysability. Dose as in GFR=10–20 mL/min |
Hepatic Dose :
No dose adjustments are recommended.