Change in Oral Absorption of Tacrolimus in a Liver Transplant Recipient After Reversal of Jejunoileal Bypass: Case Report

Effect of Jejunal Administration on Tacrolimus Trough Concentrations in a Pediatric Liver Transplant Recipient

Maintenance immunosuppression regimens containing calcineurin inhibitors, specifically tacrolimus, are standard of care for rejection prevention in pediatric liver transplantation. Challenges with tacrolimus administration are common with pediatric patients, and guidance for non-oral, enteral administration of tacrolimus is limited. We report the case of an 11-year-old male orthotopic liver transplant recipient with a history of malnutrition requiring a jejunostomy tube (J-tube) for enteral nutrition and medication administration post-transplantation. Tacrolimus was initially given orally, and then transitioned to J-tube administration for 10 days. Tacrolimus trough concentrations declined significantly following conversion to J-tube administration and remained subtherapeutic despite a 3-fold dose increase. Once transitioned back to the oral route, trough concentrations became supratherapeutic requiring dose reductions until goal concentrations were achieved. This case demonstrates reduced bioavailability and need for increased dosing, when tacrolimus is administered through a J-tube.

Liver transplantation for bariatric surgery-related liver failure: a systematic review of a rare condition

BACKGROUND

Protein malnutrition and bacterial overgrowth occurring after bariatric surgery (BS) might cause severe liver failure (LF) needing liver transplantation (LT).

OBJECTIVES

To evaluate indications and outcomes of LT for BS-related LF.

SETTING

University hospital in France.

METHODS

The EMBASE, MEDLINE, and COCHRANE central databases were systematically searched according to the PRISMA criteria from inception up through December 2017 for articles describing LT for LF after BS.

RESULTS

Fourteen studies reporting 36 patients listed for LT, of which 32 underwent the procedure, were retained. The types of previously performed BS included jejunoileal bypass (n = 16), bilio-pancreatic diversion according to Scopinaro (n = 14) or with duodenal switch (n = 3), bilio-intestinal bypass (n = 1), long-limb Roux-en-Y gastric bypass (n = 1), and single anastomosis omega gastric bypass (n = 1). Liver failure developed a median of 20 months after BS (mean ± SD: 105 ± 121 mo; range, 5-300 mo). This interval of time was significantly shorter after biliopancreatic diversion than jejunoileal bypass (mean ± SD: 22 ± 21 mo versus 269 ± 27 mo; P = .0001). Four patients (11.1%) died while on the waiting list for LT, and 4 more (12.5%) died after LT. Morbidity and liver retransplantation were reported in 8 (25%) and 2 (6.2%) patients, respectively. Twenty-one patients (65.6%) had their BS procedure reversed (1 patient before, 15 patients during, and 5 patients after LT, respectively). Biopsy-proven steatosis recurrence after LT was reported in 6 patients (18.7%), 4 of whom did not have BS reversal.

CONCLUSIONS

Severe LF occurring after BS, although rare, might require LT. When indicated, LT is effective at restoring liver function, even when BS reversal is performed synchronously.

Systematic review of drug bioavailability following gastrointestinal surgery

PURPOSE

Inter- and intraindividual pharmacokinetics variability in humans affects the way in which drugs act on the body. Gastrointestinal surgery has an impact on this variability and significantly alters the kinetics of drugs in post-surgical patients. The way in which pharmacokinetic profiles are modified depends on the type of operative procedure performed. The extent to which the absorption of different groups of drugs is affected varies according to the site and length of intestinal resections.

METHODS

A literature search was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Three databases were searched: MEDLINE, Embase, and the Cochrane Library. For each drug, potential changes in absorption were described, including recommendations extracted from the results of the studies and collected according to authors' criteria as practical conclusions, and grades of recommendation were determined by levels of evidence using the Oxford Centre for Evidence-Based Medicine scale.

RESULTS

Sixty-eight articles were collected during the selection process after the bibliographic search. The main outcomes for 60 drugs from the various studies were classified according to each type of surgery.

CONCLUSIONS

Modifications in the digestive tract secondary to gastrointestinal surgery may compromise the bioavailability of drugs. Decreased absorption surface, gastric emptying speed, and gastric pH alteration are factors to be taken into account in the management of pharmacological treatment after surgery. Evidence supported by data in clinical practice is scarce, but after studying the pharmacokinetic profile of some molecules, it is possible to offer recommendations for its adaptation to the patient's clinical situation.

Lithium toxicity after Roux-en-Y bariatric surgery

A 61-year-old woman with medical history significant for morbid obesity, type II diabetes mellitus, nephrogenic diabetes insipidus and bipolar disorder, had been stable on lithium carbonate therapy for several years. She had undergone a Roux-en-Y bypass surgery and, at the time of her surgery, her lithium level was found to be 0.61 mEq/L on a maintenance dose of 600 mg orally twice per day. She was discharged 8 days postoperatively on the same lithium dose, but presented to the emergency department 12 days postoperatively with signs of lithium toxicity. Her lithium level was elevated to 1.51 mEq/L and she was treated for lithium toxicity with supportive care and, ultimately, reduction of her lithium dose. Clinicians should be aware that dramatic and poorly understood changes in drug absorption may occur after bariatric surgery.

Vitamin, mineral, and drug absorption following bariatric surgery

The prevalence of obesity continues to rise throughout the world. Increasingly, bariatric surgery is used for those with morbid obesity as a pivotal approach to achieve weight loss. Along with substantial weight loss, malabsorption of essential vitamins, minerals, and drugs also occurs. Therefore, more than ever, a better understanding of the physiology and mechanisms by which these deficiencies occur is essential. We review the normal physiology of vitamin, mineral, and drug absorption. This is followed by a description of currently performed bariatric surgeries in the United States. A detailed review of specific nutrient and mineral deficiency states is presented, based on the most significant studies published in the last two decades. Of note, screening and supplementation recommendations have been included. Drug absorption data after these procedures is presented and discussed. Studies were identified by searching the Cochrane Registry and MEDLINE using relevant search terms, as well as through review of the reference section of included manuscripts.

CONCLUSIONS

Bariatric surgery can be effectively used to achieve sustainable weight-loss in morbidly obese patients. It simultaneously brings forth important functional consequences on nutrient deficiencies and drug absorption that clinician's must be aware of. Further prospective, randomized research on specific procedures and deficiencies is required.

Trends in oral drug bioavailability following bariatric surgery: examining the variable extent of impact on exposure of different drug classes

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Changes to oral drug bioavailability have been observed post bariatric surgery. However, the magnitude and the direction of changes have not been assessed systematically to provide insights into the parameters governing the observed trends. Understanding these can help with dose adjustments.

WHAT THIS STUDY ADDS

Analysis of drug characteristics based on a biopharmaceutical classification system is not adequate to explain observed trends in altered oral drug bioavailability following bariatric surgery, although the findings suggest solubility to play an important role.

AIMS

To identify the most commonly prescribed drugs in a bariatric surgery population and to assess existing evidence regarding trends in oral drug bioavailability post bariatric surgery.

METHODS

A retrospective audit was undertaken to document commonly prescribed drugs amongst patients undergoing bariatric surgery in an NHS hospital in the UK and to assess practice for drug administration following bariatric surgery. The available literature was examined for trends relating to drug permeability and solubility with regards to the Biopharmaceutics Classification System (BCS) and main route of elimination.

RESULTS

No significant difference in the 'post/pre surgery oral drug exposure ratio' (ppR) was apparent between BCS class I to IV drugs, with regards to dose number (Do) or main route of elimination. Drugs classified as 'solubility limited' displayed an overall reduction as compared with 'freely soluble' compounds, as well as an unaltered and increased ppR.

CONCLUSION

Clinical studies establishing guidelines for commonly prescribed drugs, and the monitoring of drugs exhibiting a narrow therapeutic window or without a readily assessed clinical endpoint, are warranted. Using mechanistically based pharmacokinetic modelling for simulating the multivariate nature of changes in drug exposure may serve as a useful tool in the further understanding of postoperative trends in oral drug exposure and in developing practical clinical guidance.

Tacrolimus trough levels before, during and after jejunostomy in a liver transplant patient: a case report

Although the feasibility of oral tacrolimus administration in the presence of jejunostomy has already been reported, few studies monitoring tacrolimus trough blood levels have been analyzed in detail, either during or after a jejunostomy closure. We report on our experience with a 34-year-old patient who underwent liver transplantations, with a proximal jejunostomy constructed a few days prior to the second transplantation. He was administered tacrolimus by a predominantly oral route, and less frequently received it by jejunostomy. The aim of this paper is to discuss this administration strategy and whether a different method could have been more suitable. This case report highlights that during the jejunostomy period, the tacrolimus doses that were required to maintain trough concentrations within the therapeutic range were four times higher than those administered after the closure of the jejunostomy. We observed an increase in the Dose-Normalized Trough Concentration (DNTC) values when tacrolimus was administered for 4 consecutive days by jejunostomy as compared to oral administration, indicating that the relative bioavailability of tacrolimus increased. Moreover, when returning to oral administration, the subsequent DNTC value was halved, highlighting a reduction in the tacrolimus bioavailability. Thus, in such a case, administration by jejunostomy could be more appropriate.

The multicenter Belgian survey on liver transplantation for hepatocellular failure after bariatric surgery

The prevalence of obesity has grown dramatically over the last decades, with nonalcoholic steatohepatitis increasingly observed. Therapeutic options for morbid obesity include bariatric surgery. Fatal liver failure (LF) has been recorded after jejunoileal bypass (JIB) but is controversial after biliopancreatic diversion (BPD, Scopinaro operation). We performed a survey on the frequency of liver transplantation (LT) after bariatric surgery in Belgium. An enquiry was sent to all Belgian liver transplant centers to investigate the occurrence of subacute and chronic LF after bariatric surgery. After weight-reduction surgery, 10 patients in 3 Belgian transplant centers were listed for LT due to severe hepatocellular failure. Nine of them had undergone a Scopinaro operation and 1 a jejunoileal bypass. The median time to develop LF was 5 years. The patient with JIB developed chronic LF after 25 years. Seven patients were transplanted; two died awaiting a graft and one is still on the waiting list. After LT, 1 patient developed rapid reappearance of LF at 10 months, requiring retransplantation. Two recipients died after LT because of multiorgan failure shortly after transplantation. In another case, a de novo cancer was fatal at 6 years' follow-up. The remaining recipients were doing well. According to this survey, the BPD operation carries a potential risk of LF. However, because there were only 10 cases, we remain unaware of the actual incidence of Scopinaro operation-induced LF. We advise strict follow-up of liver function and timely dismantling of BPD.

Species-dependent hepatic metabolism of immunosuppressive agent tacrolimus (FK-506)

The current study aims to investigate species-related differences in the in-vitro hepatic metabolism of tacroliums using liver microsomes obtained from rat, hamster, guinea pig, rabbit, pig, dog, baboon and humans. Tacrolimus metabolism was characterized using high-performance liquid chromatography- ultraviolet light (HPLC-UV) and two soft ionization mass spectrometric techniques; matrix-assisted lasers desorption/ionization (MALDI) and time-of-flight-secondary ion mass spectrometry (TOF-SIMS). The extent of tacrolimus metabolism, when normalized to the cytochrome P-450 content, was in the order: rat < hamster < rabbit < pig < guinea pig < dog < human < baboon. Tacrolimus metabolism exhibited significant qualitative and quantitative differences between the animal species tested. Desmethyl- (MI-MIII), didesmethyl- (MIV-MVI), monohydroxy- (MVII), dihydroxy- (MVIII), epoxide- (MIX), dihydrodiol- (MX), monodesmethyl and monohydroxy- (MXI-MXIII), and didesmethyl and monohydroxy- (MXIV-MXVI) tacroliums metabolites were identified in the species tested. MI-MX were identified in all the species tested; MXI-MXVI were identified in all species except rat, rabbit and guinea pig; and MXIV-MXVI were identified only in baboon. The current investigation was unable to detect any phase II metabolites due to the limitations of the test system used. The analytical methods were not able to differentiate optical and positional isomers of metabolites due to the nature of the analytical tools used, therefore groups of metabolites were identified based on their molecular weights and available information. From the current in-vitro metabolism studies, the pattern of tacroliums metabolism in baboons closely resembled that in humans and thus it is ideal for studying tacroliums metabolism-related work of clinical relevance.

A systematic review of drug absorption following bariatric surgery and its theoretical implications

Demand for bariatric surgery has risen exponentially and bariatric patients often have multiple indications for post-operative pharmacotherapy. The purpose of this study was to systematically review the published literature examining the effect of bariatric surgery on drug absorption. Studies were sought through searches of MEDLINE, EMBASE, the Cochrane Controlled Trials Registry and hand searches of reference lists. Two reviewers independently assessed studies for inclusion. Twenty-six studies (15 case reports/case series evaluating 12 different agents and 11 non-randomized controlled studies examining 15 different agents) were found. Evidence for diminished drug absorption was found in 15/22 studies involving jejunoileal bypass, 1/3 studies of gastric bypass/gastroplasty and 0/1 studies examining biliopancreatic diversion. The effect of bariatric surgery on drug absorption appears drug-specific. Drugs that are intrinsically poorly absorbed, highly lipophilic and/or undergo enterohepatic recirculation exhibited the greatest potential for malabsorption. The most consistent evidence for diminished absorption was found for cyclosporine, thyroxine, phenytoin and rifampin. Reduced drug absorption may occur post-bariatric surgery and this effect appears drug-specific. Individual dose-adjustment and therapeutic monitoring may be required. Rigorously conducted controlled studies are needed to evaluate the effect of modern bariatric procedures on drug absorption.

Significantly altered systemic exposure to atorvastatin acid following gastric bypass surgery in morbidly obese patients

The impact of gastric bypass on atorvastatin pharmacokinetics was investigated in 12 morbidly obese patients being treated with 20-80 mg atorvastatin each morning. Eight-hour pharmacokinetic investigations were performed the day before the surgery and at a median of 5 weeks (range 3-6 weeks) after the surgery. Gastric bypass surgery produced a variable effect on individual systemic exposure to atorvastatin acid (area under the plasma concentration vs. time curve from 0 to 8 h postdose (AUC(0-8))), ranging from a threefold decrease to a twofold increase (median ratio = 1.1, P = 0.99). Patients with the highest systemic exposure to atorvastatin before surgery showed reduced exposure after surgery (n = 3, median ratio = 0.4, range = 0.3-0.5, P < 0.01), whereas those with lower systemic exposure before surgery showed a median 1.2-fold increase in atorvastatin AUC(0-8) (n = 9, range = 0.8-2.3, P = 0.03) after surgery. This study indicates that the presurgical first-pass metabolic capacity influences the effect of gastric bypass on atorvastatin bioavailability. Because individual first-pass metabolic capacity is not readily assessable clinically, retitration up to the lowest effective dose should be performed after the surgery.

Laparoscopic gastric banding in a kidney-pancreas transplant recipient with new onset type II diabetes mellitus associated with morbid obesity

Combined kidney-pancreas transplantation is the treatment of choice for end-stage diabetic nephropathy. Post-transplant weight gain increases the risk for post-transplant complications and death owing to cardiovascular events. Gastric banding is an established treatment for moderate morbid obesity. We report on a patient who experienced significant weight gain and developed type II diabetes mellitus following successful kidney-pancreas transplantation. He underwent laparoscopic gastric banding and initially had good weight loss. However, lack of compliance with dietary guidelines led to transient failure of weight loss therapy. With further adjustment of the gastric band good weight loss was achieved.

Pharmacokinetics of mycophenolic acid, tacrolimus and sirolimus after gastric bypass surgery in end-stage renal disease and transplant patients: a pilot study

BACKGROUND

Promising data regarding the safety and efficacy of gastric bypass surgery (GBS) as an option to address obesity in the transplant population are emerging. The data lack on how GBS may alter the pharmacokinetics (PK) of modern immunosuppression. The objective of this study was to describe the alterations in the PK of modern immunosuppressants and the GBS population.

METHODS

Data are presented on six subjects who participated in this trial--four were on dialysis and two were renal transplant recipients. Dialysis-dependent bypass subjects received a single dose of 6 mg of sirolimus, two 4-mg doses of tacrolimus and two 1000-mg doses of mycophenolate mofetil (MMF) over the 24-h study period. Transplant recipients continued their current regimen. Maximum plasma concentration (C(max)), time to reach the maximum plasma concentration (T(max)) and the area under the plasma concentration vs. time curve (AUC(0-12) and AUC(0-infinity) where appropriate) were calculated for tacrolimus, sirolimus, mycophenolic acid (MPA) and mycophenolic acid glucuronide (MPAG).

RESULTS

Significant inter-patient variability in the C(max), T(max) and AUC of tacrolimus, sirolimus MPA and MPAG was observed. A notable difference in the AUC:dose ratio for tacrolimus was seen when comparing data with published data in the non-bypass population. Similar differences in PK were seen with sirolimus, MPA and MPAG.

CONCLUSIONS

When comparing the PK of sirolimus, tacrolimus, MPA and MPAG to published PK data in the non-bypass population, significant differences are observed. It is likely that transplant recipients with GBS would need higher doses of tacrolimus, sirolimus and MMF to provide similar exposure to a non-bypass patient.

Liver transplantation for subacute hepatocellular failure due to massive steatohepatitis after bariatric surgery

New therapeutic options for obesity include restrictive bowel surgery and surgery that promotes malabsorption, such as the Fobi-Capella (gastric bypass) and Scopinaro (biliopancreatic diversion) techniques. Complications associated with these procedures, such as hepatocellular failure, have been observed with increasing frequency. Reported here are 3 patients who, 7 to 24 months after bariatric surgery, developed hepatocellular failure, for which liver transplantation was considered to be indicated. Liver transplantation was undertaken in 2 of the patients; the third patient died while waiting for this procedure. We discuss the possible causes of this uncommon and poorly understood complication of surgery for obesity. One possibility is that it might arise as a result of progression of steatohepatitis. An alternative concept is that this complication may be secondary to rapid, massive loss of body weight.