656
Gut 2001;49:656–664
Leucopenia resulting from a drug interaction between azathioprine or 6-mercaptopurine and mesalamine, sulphasalazine, or balsalazide P W Lowry, C L Franklin, A L Weaver, C L Szumlanski, D C Mays, E V Loftus, W J Tremaine, J J Lipsky, R M Weinshilboum, W J Sandborn
Division of Gastroenterology, Division of Clinical Pharmacology, Department of Pharmacology, and Section of Biostatistics, Mayo Clinic, Rochester, MN, USA P W Lowry C L Franklin A L Weaver C L Szumlanski D C Mays E V Loftus W J Tremaine J J Lipsky R M Weinshilboum W J Sandborn Correspondence to: Dr W J Sandborn, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
[email protected] Accepted for publication 1 May 2001
Abstract Aim—We evaluated the eVect of coadministration of sulphasalazine, mesalamine, and balsalazide on the pharmacokinetics and pharmacodynamics of azathioprine and 6-mercaptopurine. Methods—Thirty four patients with Crohn’s disease receiving azathioprine or 6-mercaptopurine were enrolled in an eight week non-randomised parallel group drug interaction study and treated with mesalamine 4 g/day, sulphasalazine 4 g/day, or balsalazide 6.75 g/day. The primary outcome measure was the occurrence of clinically important leucopenia during the study, defined separately as total leucocyte counts
