Researchers from Birmingham, England, determined whether serious adverse effect profiles differ for the 5-aminosalicylates, sulphasalazine and mesalazine.
These drugs are extensively prescribed for the treatment of ulcerative colitis.
An analysis of suspected serious adverse reactions, reported to the Committee on Safety of Medicines of the United Kingdom between 1991 and 1998, was performed.
In addition, adverse effect profiles were categorized for interstitial nephritis, pancreatitis, serious skin reactions, hepatitis and hepatic failure, and blood dyscrasias.
Report rates were calculated using prescribing data from the Department of Health and then compared for mesalazine and sulphasalazine.
In total, 4.7 million prescriptions were dispensed for sulphasalazine compared with 2.8 million for mesalazine.
Interstitial nephritis only occurred in patients taking mesalazine, at a rate of 11.1 reports per million prescriptions dispensed.
| Pancreatitis 7-times more likely with mesalazine than sulphasalazine.
Pancreatitis was reported 7 times as frequently for mesalazine (7.5 per million prescriptions) compared with sulphasalazine (1.1 per million prescriptions).
The authors found no reports of serious skin disorders in patients prescribed sulphasalazine for inflammatory bowel disease.
However, blood dyscrasias occured significantly more often in patients receiving sulphasalazine for rheumatoid arthritis than for inflammatory bowel disease (odds ratio, 5.31). There was also a similar trend for hepatic disorders.
In this report, researchers Ransford and Langman from Queen Elizabeth Hospital, Birmingham, comment that pancreatitis and interstitial nephritis appear significantly more common with mesalazine.
They suggest that renal monitoring in patients who receive mesalazine may need reinforcing.
Given the evidence, there is nothing to indicate a safety advantage of mesalazine over sulphasalazine in the treatment of inflammatory bowel disease, they conclude.