Crohn's Disease: From an Anesthetist’s Perspective

Abstract

Crohn's Disease 104 3. Interaction beetween anti-Crohn's drugs and anesthetic drugs 3.1 Aminosalicylates Sulfasalazine and mesalamine are the two aminosalicylates used for Crohn's disease. The primary antiinflammatory, antipyretic, and analgesic actions of salicylates such as aspirin are due to blockade of prostaglandin synthesis by inhibition of the cyclooxygenase 1 and 2 enzymes. These are effective in maintaining remission in patients with mild-to-moderate diseases (4). Studies demonstrate that both mesalamine and sulfasalazine are efficacious at inducing and maintaining remission, and are often used as long-term maintenance treatments. The improved side effect profile of mesalamine has enabled the use of doses that are much higher in amount than doses possible with sulfasalazine. However, a number of cases of 5-ASA-induced nephrotoxicity have been reported in patients with inflammatory bowel disease (IBD) (5, 6). Several case reports have reported renal impairment in the forms of dose-dependent 'analgesic nephropathy', inhibition of cyclooxygenases or hypersensitivity leading to reversible interstitial nephritis in humans. The incidence of renal impairment in patients with IBD treated with 5-ASA is estimated to be one in 100 patients, and interstitial nephritis occurs in one in 500 patients (7, 8). M a h m u d e t a l , w e r e u n a b l e t o s h o w n e p h r o toxicity after six months of mesalamine treatment in patients with ulcerative colitis using a low dose of 1.2 g/day (9). Similarly, Van Staa et al, were not able to demonstrate a relationship between the dose or type of 5-ASA and the incidence of renal disease among 19,025 IBD patients on 5-ASA (10). Based on their findings, interstitial nephritis related to 5-ASA use appears to be a rare event. Although interstitial nephritis occurs infrequently, renal function can be compromised over time with the use of 5-ASA. According to a recent report, de Jong et al, did not find a significant change in creatinine clearance (CrCl) over an 11-year interval in 200 patients with Crohn's disease (11). However, the mean duration of treatment with 5-ASA was 8.6 years, much shorter than the interval that CrCl was measured. This may reflect why the decline in CrCl was reported to be within the expected physiological decline in renal function associated with aging. Fortunately, the kidneys have the capacity to regain function after an insult; thus, creatinine measurements need to be taken at the onset and end of treatment rather than time points outside of the actual treatment interval. Also, no case of interstitial nephritis was reported by same author (11). In brief, the time of development of renal impairment is variable and may be seen as late as after several years. There is also a risk of developing irreversible renal disease if not recognized early, in which discontinuation of 5-ASA could result in recovery of renal function. Monitoring serum creatinine provides an easy and inexpensive way to prevent a detrimental side effect.