Bowel Preparation Agents Research Articles

Predictors of Inadequate Bowel Preparation and Salvage Options on Colonoscopy

Inadequate bowel preparation is observed in more than 25% of all colonoscopies. Identification of predictive factors for inadequate colon cleaning is helpful and more detailed preparation methods should be used for patients at high risk. Age, male sex, inpatient status, and comorbidities were identified as independent risk factors in several previous studies. In patients with insufficient colon preparation, colon irrigation with endoscopic pumps or next-day colonoscopy following further bowel cleaning should be performed. In order to improve the efficacy and safety of both bowel preparation and colonoscopy, the endoscopic team should identify the patient’s medical conditions and choose the optimal bowel preparation agent and regimen.

Sodium phosphate versus polyethylene glycol for colonoscopy bowel preparation: an updated meta-analysis of randomized controlled trials.

Adequate bowel cleansing is of great importance for a high-quality colonoscopy examination. Nevertheless, whether sodium phosphate or polyethylene glycol is a gold standard agent for bowel preparation is still under debate. In consideration of the clinical needs, we thus performed an updated meta-analysis of randomized controlled trials concerning the comparison between both regimens. The efficacy, safety and acceptability of each regimen are major indicators to measure and appraise. By searching PubMed, EMBASE, Web of Science and Cochrane Library databases, 15 original trials published from 2000 to 2014 were included as eligible studies. We carried out data extraction and subsequent pooling analysis for each indicator in a standard manner. Sensitivity analysis was performed by elimination of low-quality trials, while a funnel plot and Egger's test were employed to analyze the publication bias across studies. Our pooling analysis revealed that patients undergoing sodium phosphate as a cleansing agent displayed better acceptability, compliance, cleansing scores, preparation taste, polyp detection rate and less adverse effects including nausea, vomiting and abdominal pain (P<0.05). In terms of procedure time, adequate preparation rate and electrolyte concentration, there was no significant difference between both regimens (P>0.05). The pooling analysis offered stable conclusions which were verified by our sensitivity analysis. There was no publication bias across studies as a symmetric funnel plot was demonstrated and the result of Egger's test was P=0.56. Regarding preparation efficacy, safety and acceptability, sodium phosphate was a better agent than polyethylene glycol for colonoscopy bowel cleansing, with its advantages of higher efficacy, better tolerability and acceptability as well as comparable safety.

One Day Polyethylene Glycol-3350 for Bowel Preparation in Pediatrics: A Literature Review

Bowel preparation for colonoscopy in children is a challenging procedure. Wide variety of preparation protocols exist, varying with the hospital. Unlike in adults, there is a lack of uniform bowel preparation protocol in children. Ideally, the bowel preparation agents are assessed by their safety, efficacy and tolerability. Unfortunately, none of the preparations currently available meets all of these criteria. However, since last decade, Polyethylene Glycol-3350 (PEG-3350) is gaining popularity for bowel preparation with reported safety, efficacy, and tolerability. The only major drawback of PEG-3350 without electrolyte was 4 days long preparation time thus raising the question if the duration of preparation time could be minimized and yet have same efficacy, safety, and tolerability of the medicine. Hence, one day PEG-3350 regimen was introduced eventually and is now being studied with increased dosage or combined with other laxatives. This is the first review which compiles the study so far conducted on one day PEG-3350 without electrolyte as colonoscopy bowel preparation in children and tries to summaries if this regimen can be commonly used in children for colonoscopy bowel preparation.

Randomized Controlled Trial of Sodium Phosphate Tablets versus 2 L Polyethylene Glycol Solution for Bowel Cleansing prior to Colonoscopy

Performance of polyethylene glycol solution (PEG) is often unsatisfactory as bowel preparation agent for colonoscopy. In order to provide equivalent efficacy with better patient tolerance, sodium phosphate tablet (SPT) has been developed. This study was carried out to compare the efficacy and compliance of two bowel preparation methods: PEG with ascorbic acid (PEGA) vs. SPT preparation. A multicenter, randomized controlled trial was performed. Primary efficacy variable was overall quality of colon cleansing assessed by Boston bowel preparation scale (BBPS) during colonoscopy. Patient's satisfaction and adverse events were evaluated by means of symptom questionnaire completed by each patient immediately before colonoscopy. A total of 189 patients were randomly assigned to undergo pre-colonoscopic bowel preparation with either SPT (n = 96) or PEGA (n = 93). Overall BBPS score was 8.3 ± 1.12 in the SPT group and 8.4 ± 0.96 in the PEGA group (p = 0.441). Among the 189 patients, 90 had polyps (47.6%) and 50 had adenomas (26.5%). The polyp/adenoma detection rate was 54.2% (n = 52)/27.1% (n = 26) for SPT group and 40.9% (n = 38)/25.8% (n = 24) for PEGA group (p = 0.079 and 0.790, respectively). More number of patients were unable to take the prescribed dose of PEGA compared with the SPT regimen (8.6% vs. 2.0%, p = 0.045). Overall satisfaction score was 7.9 ± 1.63 in the SPT group and 7.4 ± 1.53 in the PEGA group (p = 0.022). Degree of colon preparation, polyp/adenoma detection rate and adverse effect were similar between SPT group and PEGA group. Patient compliance and satisfaction were greater in the SPT group.

Achieving the best bowel preparation for colonoscopy.

Bowel preparation is a core issue in colonoscopy, as it is closely related to the quality of the procedure. Patients often find that bowel preparation is the most unpleasant part of the examination. It is widely accepted that the quality of cleansing must be excellent to facilitate detecting neoplastic lesions. In spite of its importance and potential implications, until recently, bowel preparation has not been the subject of much study. The most commonly used agents are high-volume polyethylene glycol (PEG) electrolyte solution and sodium phosphate. There has been some confusion, even in published meta-analyses, regarding which of the two agents provides better cleansing. It is clear now that both PEG and sodium phosphate are effective when administered with proper timing. Consequently, the timing of administration is recognized as one of the central factors to the quality of cleansing. The bowel preparation agent should be administered, at least in part, a few hours in advance of the colonoscopy. Several low volume agents are available, and either new or modified schedules with PEG that usually improve tolerance. Certain adjuvants can also be used to reduce the volume of PEG, or to improve the efficacy of other agents. Other factors apart from the choice of agent can improve the quality of bowel cleansing. For instance, the effect of diet before colonoscopy has not been completely clarified, but an exclusively liquid diet is probably not required, and a low-fiber diet may be preferable because it improves patient satisfaction and the quality of the procedure. Some patients, such as diabetics and persons with heart or kidney disease, require modified procedures and certain precautions. Bowel preparation for pediatric patients is also reviewed here. In such cases, PEG remains the most commonly used agent. As detecting neoplasia is not the main objective with these patients, less intensive preparation may suffice. Special considerations must be made for patients with inflammatory bowel disease, including safety and diagnostic issues, so that the most adequate agent is chosen. Identifying neoplasia is one of the main objectives of colonoscopy with these patients, and the target lesions are often almost invisible with white light endoscopy. Therefore excellent quality preparation is required to find these lesions and to apply advanced methods such as chromoendoscopy. Bowel preparation for patients with lower gastrointestinal bleeding represents a challenge, and the strategies available are also reviewed here.

Randomized controlled trial of low-volume bowel preparation agents for colonic bowel preparation: 2-L polyethylene glycol with ascorbic acid versus sodium picosulfate with magnesium citrate

Both 2-L polyethylene glycol with ascorbic acid (2-L PEG/Asc) and sodium picosulfate with magnesium citrate (SP/MC) are low-volume combined agents for colonic preparation. The aim of the current study was to compare the preparation adequacy and patient tolerability of 2-L PEG/Asc and SP/MC. We performed a prospective randomized controlled study in outpatients undergoing daytime colonoscopy at a tertiary academic hospital. We compared preparation adequacy based on the Boston Bowel Preparation Scale (BBPS), polyp and adenoma detection rate (PDR and ADR), compliance, tolerability for ease and palatability, intention to reuse, and patient satisfaction using a questionnaire between 2-L PEG/Asc and three sachets of SP/MC, both given in a split-dose method. A total of 388 patients were evaluated based on intention to treat (ITT) and 356 patients per protocol (PP). No significant differences in preparation adequacy were observed in ITT and PP analyses, based on the BBPS (p > 0.05). The PDR and ADR were greater than 60 and 40% in both groups, respectively (p > 0.05). Compliance levels were higher in the 2-L PEG/Asc group than in the SP/MC group (p < 0.001). Satisfaction (ITT, p = 0.014; PP, p = 0.032) and palatability (ITT and PP, p < 0.001) levels were higher in the SP/MC group than in the 2-L PEG/Asc group, but values for tolerability for ease and intention to reuse were similar in both groups (ITT and PP, p > 0.05). Both 2-L PEG/Asc and SP/MC had adequate bowel cleansing efficacy to satisfy PDR and ADR as quality indicator and had showed similar tolerability.

Polyethylene glycol vs sodium picosulfate/magnesium citrate for colonoscopy preparation.

Background and study aims: Polyethylene glycol-based electrolyte solutions (PEG-ELS) and the combination of sodium picosulfate/magnesium citrate (SPMC) are commonly used bowel preparation agents. The aim of the present study was to compare the two agents with regard to cleansing efficacy and tolerance among individuals scheduled for outpatient colonoscopy. Materials and methods: The 368 colonoscopy outpatients at three Norwegian hospitals were randomized to bowel lavage with either PEG-ELS or SPMC. Compliance and patient tolerance were evaluated using a patient questionnaire. Bowel cleansing was evaluated using the Ottawa Bowel Preparation Quality Scale (OBPS), a validated scoring system with scores between 0 (best) and 14. Results: There was no difference in the cleansing quality between the PEG-ELS and SPMC groups (median OBPS 5.0 in both groups). The group that received SPMC reported better overall patient tolerance than the PEG-ELS group (72.6 % vs 59.0 % reporting no or slight discomfort, P < 0.01). Compliance with the recommended total fluid intake (4 L) was better in the SPMC group than in the PEG-ELS group (94.2 % vs 81.2 % respectively, P < 0.01); moreover, the polyp detection rate was superior (34.3 % vs 23.3 %, P = 0.02). Conclusion: PEG-ELS and SPMC are equally effective in cleansing efficacy, but SPMC was better tolerated by patients and resulted in superior patient compliance and polyp detection rate.Clinical trial registration: NCT01624454

The evolution of bowel preparation and new developments.

Bowel preparation is essential for successful colonoscopy examination, and the most important factor is the bowel preparation agent used. However, selection of a bowel preparation agent invariably involves compromise. Originally, bowel preparation was performed for radiologic and surgical purposes, when the process involved dietary limitations, cathartics, and enemas, which had many side effects. Development of polyethylene glycol (PEG) solution led to substantive advancement of bowel preparation; however, despite its effectiveness and safety, the large volume involved, and its salty taste and unpleasant odor reduce compliance. Accordingly, modified PEG solutions requiring consumption of lower volumes and sulfate-free solutions were developed. Aqueous sodium phosphate is more effective and better tolerated than PEG solutions; however, fatal complications have occurred due to water and electrolyte shifts. Therefore, aqueous sodium phosphate was withdrawn by the US Food and Drug Administration, and currently, only sodium phosphate tablets remain available. In addition, oral sulfate solution and sodium picosulfate/magnesium citrate are also available, and various studies have reported on adjunctive preparations, such as hyperosmolar or stimulant laxatives, antiemetics, and prokinetics, which are now in various stages of development.

Adjuncts to colonic cleansing before colonoscopy

Pre-procedural cleansing of the bowel can maximize the effectiveness and efficiency of colonoscopy. Yet, efficacy of the current gold standard colonic preparation method - high-volume oral administration of purgative agents 12-24 h prior to the procedure - is limited by several factors, such as patient compliance (due to poor palatability and inconvenience of the dosing regimen) and risks of complications (due to drug interactions or intolerance). Attempts to resolve these limitations have included providing adjunctive agents and methods to promote the colonic cleansing ability of the principal purgative agent, with the aim of lessening unpleasant side effects (such as bloating) and reducing the large ingested volume requirement. Several promising adjunctive agents are bisacodyl, magnesium citrate, senna, simethicone, metoclopramide, and prokinetics, and each are being investigated for their potential. This review provides an up to date summary of the reported investigations into the potencies and weaknesses of the key adjuncts currently being applied in clinic as supplements to the traditional bowel preparation agents. While the comparative analysis of these adjuncts showed that no single agent or method has yet achieved the goal of completely overcoming the limitations of the current gold standard preparation method, they at least provide endoscopists with an array of alternatives to help improve the suboptimal efficacy of the main cleansing solutions when used alone. To aid in this clinical endeavor, a subjective grade was assigned to each adjunct to indicate its practical value. In addition, the systematic review of the currently available agents and methods provides insight into the features of each that may be overcome or exploited to create novel drugs and strategies that may become adopted as effective bowel cleansing adjuncts or alternatives.

Frustration still exists.

See Article on Page 222-227 The history of colonoscopy could be the history of bowel preparation. In fact, the evolution of bowel preparation is much longer than the history of colonoscopy. Bowel preparation was also inevitable in the era of radiological colon study. Along with the progress in colonoscopy, various studies of bowel preparation have been done. The main emphases of those bowel-cleansing studies were drugs or regimens and administration methods. A single agent or combined regimens have been tried in various ways. In fact, the agents are not as diverse as the colonoscopic procedures. An unavoidable limitation of drugs or agents is that must they do no harm to the human body and be sufficiently effective [1]. This article addresses the single and the combined use of a polyethylene glycol solution and a sodium picosulfate with magnesium citrate solution. The authors reported good results for the sodium picosulfate/magnesium citrate solution, even for its single use [2]. Sodium picosulfate with magnesium citrate is not a novel agent and has already been reported to be an efficient precolonoscopy bowel-preparation agent [3]. However, the study is still worthwhile because the importance of bowel preparation cannot be underestimated in any practical colonoscopies. In other words, bowel cleansing is the basic procedure for successful colonoscopic diagnosis and treatment. Many patients used to say that the colonoscopy itself was bearable, but the process of bowel preparation was a real pain. That was reality! Bowel cleansing is time consuming, uncomfortable and stressful. As a matter of fact, despite the existence of various bowel-cleansing methods, we still experience frustrating situations for patients and even for doctors. Accordingly studies should be continued. Although the efficacies of the drugs and of the administration methods are the key points, practical points, such as the planned timetable and schedules, could be obstacles to bowel cleansing. In short, frustration still exists in bowel preparation. A tailored approach could be helpful. Patience and sincerity are needed for colonoscopists, assisting staff members and patients themselves. The basic principle is important and still remains as an issue.

PTH-047 A Prospective Study on the Impact of a ‘Bowel Cleansing Care Bundle’ on Inpatient Colonoscopy Visualisation Scores: A London District Hospital Experience

IntroductionIt is recognised that a well prepared colon increases adenoma detection and removal rates1 and the discovery of other significant pathology at endoscopy. Several factors can lead to a suboptimal...

Tu1375 Bowel Preparation With Polyethylene Glycol (PEG) Injection After Upper Gastrointestinal Endoscopy: a Pilot Study

The use of polyethylene glycol (PEG) in large volumes is required for bowel preparation prior to colonoscopy and is associated with considerable gastrointestinal (GI) distress. Therefore, a variety of approaches are currently being explored to address this issue, which include the development of novel bowel preparation agents or the use of PEG in reduced doses.

Mechanical Bowel Preparation: Keep It or Abandon It?

See Article on Page 161-167 Until recently, vigorous preoperative mechanical cleansing of the bowel, together with or without the use of oral antibiotics, was thought to reduce the risk of septic complications after colorectal surgery. However, well-designed clinical trials regarding mechanical bowel preparation (MBP) started to be published from 1972, and their results caused some colorectal surgeons to doubt this long-standing custom. From 2003, Guenaga et al. [1], using the Cochrane database, reported four times on the use of MBP for elective colorectal surgery. They concluded that there was no statistically significant evidence that patients benefited from MBP or from the use of rectal enemas. However in a 2003 survey, the American Society of Colon and Rectal Surgeons estimated that 99% of its members still prescribed some type of MBP and that 75% used oral antibiotic prophylaxis as part of their standard preoperative protocol for elective colorectal surgery [2]. Also, the authors revealed that most of the respondents (90%) from a Korean national survey were in favor of a preoperative MBP procedure and that 49% of the respondents agreed with the use of oral antibiotics [3]. Despite of the many studies insisting that MBP has no usefulness, current clinical practice does not follow any guideline. This may be explained as the 'no more MBP' concept being beyond surgeons' common sense feeling that the surgical field should be protected from contamination sources to prevent infection-related complications. There are several practical issues concerning the MBP procedure. Firstly, MBP procedures vary among clinicians. Thus, standardization for the MBP procedure is very much needed. Secondly, novel bowel preparation agents, Coolprep (polyethylene glycol solution + ascorbic acid), Picolyte (sodium picosulphate + magnesium citrate), have been introduced into clinical practice from 2012. These agents reduced the inconvenience to the patients. However, the effectiveness and safety of MBP using these agents for colon surgery are not well known. Despite the availability of several different products for colon cleansing, a need for a better regimen that provides excellent colon cleansing without tolerability and safety concerns continues to exist. Thirdly, most of colorectal surgery is conducted by using a laparoscopic technique. However, data on MBP in patients submitted for rectal surgery and laparoscopic colorectal surgery are not sufficient. Lastly, enhanced recovery after surgery (ERAS) is well established and has been developed to optimize perioperative care and to facilitate discharge. According to ERAS society's recommendations, preoperative MBP should not be used routinely in colorectal surgery [4]. In addition, the application of this recommendation to Korean patients must be verified. In conclusion, more convincing data are required if MBP is to be abandoned. As the authors point out, members of the Korean Society of Coloproctology should make an effort to establish Korean guidelines for the use MBP. Large-scale prospective randomized trials should be conducted to achieve this purpose.

A Validated Bowel-Preparation Tolerability Questionnaire and Assessment of Three Commonly Used Bowel-Cleansing Agents

Bowel-cleansing studies are frequently underpowered, poorly designed, and with subjective assessments. Consensus on tolerability of the bowel-cleansing agents is thus lacking. This study developed and validated a bowel-preparation tolerability questionnaire and used it to assess the tolerability of three bowel-cleansing agents, sodium phosphate (NaP), polyethylene glycol (PEG), and sodium picosulphate (Pico), in a prospective randomized single-blinded trial of ambulatory patients. The bowel-preparation tolerability questionnaire was validated in 125 consecutive patients and then bowel-preparation agent tolerability was assessed in 634 patients in a prospective randomized single-blinded trial. The questionnaire's internal consistency was satisfactory with good to excellent "test-retest" reliability for aggregate tolerability and visual analogue scores. Validity assessment confirmed it as reliable and accurate. Of 634 patients, 97.8 % took >75 % of the allocated preparation and 98.9 % completed the questionnaire. Overall, Pico was better tolerated than PEG (p < 0.001) and NaP (p < 0.001). NaP was better tolerated than PEG (p < 0.001). Regardless of the bowel-preparation agent used, males tolerated them better than females (p = 0.009) as did patients having their procedure in the AM. Older patients, however, tolerated all preparations better than younger patients (p = 0.006). This study used the first validated bowel-preparation tolerability questionnaire and identified that age, sex, and procedure time all impacted tolerability. Overall, Pico was best tolerated, but PEG's tolerability in patients ≥60 years was equal to that of Pico and NaP, suggesting that PEG can be recommended for older patients to avoid the electrolyte disturbances associated with the osmotic preparations.

Usefulness of sennoside as an agent for mechanical bowel preparation prior to elective colon cancer surgery

We retrospectively evaluated the usefulness of sennoside as an agent for mechanical bowel preparation prior to elective colon cancer surgery. A total of 86 patients were given 12 mg of sennoside on the evening prior to resective surgery for colon cancer, followed by intravenous antimicrobial prophylaxis used on the day of surgery or until postoperative day 2. The incidence of surgical site infection in the study group was 4.7%, which was comparable to that in the historical control patients (3.5%, p>0.99), who had received polyethylene glycol for mechanical bowel preparation prior to colon surgery. On multivariate logistic regression analysis, only body mass index (p=0.04) was an independent significant factor affecting the surgical site infection. The intraoperative spillage was not influenced by the presence of stenosis, although the amount of fecal matter was higher in the upstream colon segment (p<0.01) and downstream segment (p=0.07) in patients with a stenotic lesion occupying more than two-thirds of the lumen (n=29) than in those without such severe stenosis (n=57). Sennoside seems to be an acceptable agent for mechanical bowel preparation even in patients with stenosis.

How to avoid common pitfalls with bowel preparation agents

Colonoscopy is the driving force of our specialty, and gastroenterologists are obliged to perform a high-quality colonoscopy to ensure the future of conventional colonoscopy. In addition, quality colonoscopy protects against colorectal cancer incidence and mortality. The quality of examination during colonoscopy can be impaired by imperfect bowel preparation. Steps to improve patient understanding of and compliance with bowel preparation could significantly improve the outcomes of colonoscopy in clinical practice.

The Timing of Bowel Preparation Is More Important than the Timing of Colonoscopy in Determining the Quality of Bowel Cleansing

We aimed to compare the quality of bowel preparation and cecal intubation rates between morning and afternoon colonoscopies and to evaluate the difference in quality of bowel preparation according to the intervals between starting and ending intake of bowel preparation agent and the initiation of colonoscopy. In this prospective study, 300 outpatients were instructed to drink PEG solution starting either at 5:00 a.m. (morning group) or at 8:00 a.m. (afternoon group) on the same day. The time when PEG intake was started and completed, and when colonoscopy was begun were recorded. The quality of bowel preparation was assessed using the Ottawa bowel preparation scale. There was no significant difference in the Ottawa scale between the morning and the afternoon groups (p = 0.14). Patients with intervals of 7 h or less between the initiation of PEG intake and the start of colonoscopy had a better quality of bowel preparation than those with intervals of more than 7 h (p = 0.03). In addition, patients with intervals of 4 h or less between the end of PEG intake and the start of colonoscopy had a better quality of bowel preparation than those with intervals of more than 4 h (p = 0.02). The time of day at which colonoscopy is performed, whether during the morning or the afternoon, does not have a significant impact on the quality of bowel preparation. The quality of bowel preparation is significantly better in patients with a shorter time between bowel preparation and the start of colonoscopy.

Bowel Preparation and Prokinetic Agents for Small Bowel Capsule Endoscopy

Bowel Preparation and Prokinetic Agents for Small Bowel Capsule Endoscopy

Duration of the interval between the completion of bowel preparation and the start of colonoscopy predicts bowel-preparation quality

Recent studies suggest that colonoscopies done in the morning have better-quality bowel preparations than those done in the afternoon. We aimed to determine how the duration of the interval between the end of the preparation and the start of the colonoscopy affects preparation quality. We prospectively studied consecutive outpatients who had colonoscopies performed at our hospital within a 3-month period. The time of day when the colonoscopy started and the time interval from the last dose of preparation agent to the start of the colonoscopy were recorded. The endoscopist graded the quality of the preparation in the right side of the colon by using a 5-point visual scale. We studied 378 patients (96% men, mean age 62.2 years) who received preparations of polyethylene glycol electrolyte-based (PEG) and sodium phosphate (SP) solution (71%), oral PEG and magnesium citrate (23%), or SP alone (6%). Compared with patients whose preparations were graded as 2/3/4 (fair/poor/inadequate), those whose preparations were graded as 0/1 (excellent/good) had a significantly shorter interval between the time of the last preparation agent dose and the start of the colonoscopy (P = .013). We used a nonvalidated scale to assess the quality of bowel preparation. Bowel-preparation quality varies inversely with the duration of the interval between the last dose of the bowel-preparation agent and the start of colonoscopy. This interval appears to be a better predictor of bowel-preparation quality than the time of day when colonoscopy is performed.

Should We Be Using Bowel Preparation and Prokinetic Agents for Small Bowel Capsule Endoscopy? A Prospective Randomized Controlled Trial

randomized to PEG, OSPS, or dual (OSPSþPEG) preparations. Subjects with GFR %60 ml/min were not randomized to OSPS or dual preparation. Blood and early morning spot urine were collected 1 wk prior to (v1), on day of (v2) and 1 wk after C (v3) for serum creatinine (Cr, mg/dL), estimated glomerular filtration rate (eGFR, ml/min), phosphorous (P, mg/dL), calcium (Ca, mg/dL) with urinary P, creatinine, and N-acetyl-Dglucosaminidase (NAG, IU/mg of creatinine), a lysosomal enzyme released in urine after tubular injury. Effect on renal function was assessed by absolute change in Cr, percent change in Cr and eGFR at v2 and v3 compared to v1. Results: A total of 165 subjects (AB Z 139; mean age: 58 1 y and SCI Z 26; mean age: 60 2y; p Z 0.3) were analyzed. Bowel preparation was achieved with PEG in 55 (AB Z 47; SCI Z 8), OSPS in 55 (AB Z 47; SCI Z 8), and dual in 56 (AB Z 46; SCI Z 10) subjects. In AB subjects, Cr at v2 increased with OSPS (0.9 0.2 to 0.94 0.3) and dual (0.9 0.2 to 0.91 0.2) preparation, but decreased in SCI subjects (0.7 0.2 to 0.6 0.2) and returned to baseline by v3. Absolute change in Cr at v2 was higher in AB subjects compared to SCI with OSPS (0.01 0.02 vs -0.09 0.03, p ! 0.04) and dual (0.04 0.03 vs. -0.1 0.05, p ! 0.07). Percent change in Cr was higher with OSPS (2.1 2.2 vs -12 4.6, p ! 0.01) and dual (4 3.4 vs. -12 6.3, p ! 0.03) but not with PEG (2.1 2.2 vs. -12 4.5, p O 0.1). Changes in eGFR paralleled Cr changes. In AB subjects, OSPS increased serum P (3.2 0.5 to 5.7 1.7, p ! 0.0001), urinary P (67 6 to 405 40, p ! 0.0001), urinary NAG (0.4 0.05 to 0.6 0.1, p ! 0.02) and decreased serum Ca (9.2 0.4 to 8.8 8.8 0.4m p ! 0.0005) at v2. Similar trends were seen with dual but not with PEG. With OSPS in SCI subjects, changes in serum P (increase) and Ca (decrease) were similar to AB subjects without significant change in urinary P or NAG. Conclusion: Ingestion of OSPS alone or in combination with PEG resulted in elevation of serum P with decrease in Ca in AB and SCI subjects. Transient, but clinically insignificant, deterioration of renal function occurs in AB subjects. SCI subjects are less predisposed to this toxicity of OSPS and use of OSPS appears to be safe for routine C in them.