Original ArticlesDose-Adjusted Cyclosporine C2 in a Patient with Jejunoileal Bypass as Compared to Seven Other Liver Transplant RecipientsChenhsu, Rou-Yee; Wu, Youmin MD; Katz, Daniel MD; Rayhill, Stephen MDAuthor Information From the Department of Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa. Received for publication March 27, 2003; accepted May 23, 2003. Reprints: Rou-Yee Chenhsu, Organ Transplantation, Department of Surgery, University of Iowa Hospitals and Clinics, 200 Hawkins Drive, 1527 JCP, Iowa City, IA 52242-1086. Therapeutic Drug Monitoring: December 2003 - Volume 25 - Issue 6 - p 665-670 Buy Abstract Jejunoileal bypass (JIB) is a weight loss procedure in which malabsorption is produced by connecting a short length of proximal jejunum to the distal ileum. Because 90% of the small intestine is bypassed, it may have impact on the dose–concentration response of oral cyclosporine (CsA). The authors characterized the dose-adjusted blood concentrations of CsA obtained 2 hours (C2) after oral microemulsion CsA (ME-CsA) in a liver transplant (LTx) subject with an intact JIB, as compared with those from seven LTx controls without JIB. The biliary reconstruction involved choledochocholedochostomy without external drainage in all patients. ME-CsA was administered via a nasogastric tube within 24 hours after graft reperfusion. Oral fluconazole was given prophylactically to the study subject only for 6 days after LTx. During the first week after LTx, the dose-adjusted C2 (mean ± SD) for the study subject and for controls was 53 ± 10 and 106 ± 47 ng/mL, respectively (P < 0.001). The corresponding value during the period from day 7 to day 107 was 105 ± 40 and 257 ± 86 ng/mL, respectively (P < 0.001). Multiple linear regression revealed that dosage, days after LTx, and the presence of a JIB were all independent predictors of C2 (R2 = 0.798, P = 0.037). Lack of bile resulting in malabsorption of ME-CsA was not thought to be significant contributor to her low dose-adjusted C2 because there was no external bile drainage and a portion of terminal ileum, where most bile acid reabsorption occurred, was still available after JIB. The fact that fluconazole failed to increase the dose-adjusted C2 in the study subject supports that enteric clearance of CsA may become clinically unimportant after JIB. Therefore, the low dose-adjusted C2 is most likely explained by the reduced bowel length and associated absorptive surface area after JIB. In conclusion, patients with JIB may require higher doses of ME-CsA. © 2003 Lippincott Williams & Wilkins, Inc.