World MJ, Stevens PE, Ashton MA, Rainford DJ
Mesalazine associated interstitial nephritis
Nephrol Dial Transplant
(Apr) 11:614-621 1996

Mesalazine (5-aminosalicylic acid, 5-ASA) is effective in the
treatment of inflammatory bowel disease. Enteric coated preparations
delay the release of the salicylate until the drug enters the terminal
ileum or colon. World et al report four patients who developed
interstitial nephritis while being treated with 5-ASA. They review 12
previously reported cases. This report indicates that renal
impairment may occur in as many as 1 in 100 patients, but that severe
renal insufficiency only occurs in less than 1 in 500 patients. They
observed that the only reliable indicator of 5-ASA induced toxicity
is an increase in the serum creatinine concentration. Recovery of
renal function was related to the duration of unrecognized renal
injury. Patients who continued taking 5-ASA for longer that 18
months after the onset of toxicity did not recover renal function.
Comment: Mesalazine induced interstitial nephritis is an
insidious process. Normal urinalysis and the absence of typical
features of drug allergy make the diagnosis of mesalazine induced
interstitial nephritis more difficult. Since elevation of the serum
creatinine may be the earliest and possibly the only manifestation,
it should be measured monthly for the first three months after
initiation of treatment with 5-ASA, every three months thereafter for
a year, and at least yearly for the duration of treatment. (George
R. Aronoff, M.D., University of Louisville, Kentucky)