Quantitative appraisal of Picolax (sodium picosulfate/magnesium citrate) in the preparation of the large bowel for elective surgery

Hyponatremia and sodium picosulfate bowel preparations in older adults

OBJECTIVES

Bowel preparations are commonly prescribed drugs. Case reports and our clinical experience suggest that sodium picosulfate bowel preparations can precipitate severe hyponatremia in some older adults. At present, this risk is poorly quantified. We investigated the association between sodium picosulfate use and the risk of hyponatremia in older adults.

METHODS

We conducted a population-based retrospective cohort study using six linked administrative databases in Ontario, Canada. All Ontario residents over the age of 65 years who filled an outpatient bowel preparation prescription before colonoscopy were eligible. We enrolled new users of either sodium picosulfate (n=99,237) or polyethylene glycol (n=48,595). The primary outcome was hospitalization with hyponatremia within 30 days of the bowel preparation assessed by database codes. The secondary outcomes were hospitalization with urgent head computed tomography (CT) (a proxy for acute central nervous system disturbance) and all-cause mortality.

RESULTS

The baseline characteristics of the two groups, including patient demographics, comorbid conditions, and concomitant medications, were nearly identical. Compared with polyethylene glycol, sodium picosulfate was associated with a higher risk of hospitalization with hyponatremia (absolute risk increase: 0.05%, 95% confidence interval (CI): 0.04-0.06%, relative risk (RR): 2.4, 95% CI: 1.5-3.9), but not hospitalization with urgent CT head (RR: 1.1, 95% CI: 0.7-1.4) or mortality (RR: 0.9, 95% CI: 0.7-1.3).

CONCLUSIONS

Sodium picosulfate bowel preparations lead to more hyponatremia than polyethylene glycol. There was no evidence of increased risk of acute neurologic symptoms or mortality. The absolute increase in risk of hospitalization with hyponatremia remains low but may be avoidable through appropriate fluid intake or preferential use of polyethylene glycol in some older adults.

Sodium picosulfate/magnesium citrate: a review of its use as a colorectal cleanser

Oral sodium picosulfate/magnesium citrate (CitraFleet; Picolax), consisting of sodium picosulfate (a stimulant laxative) and magnesium citrate (an osmotic laxative), is approved for use in adults (CitraFleet; Picolax) and/or adolescents and children (Picolax) as a colorectal cleansing agent prior to any diagnostic procedure (e.g. colonoscopy or x-ray examination) requiring a clean bowel and/or surgery. It is dispensed in powder form (sodium picosulfate 0.01 g, magnesium oxide 3.5 g, citric acid 12.0 g per sachet), with the magnesium oxide and citric acid components forming magnesium citrate when the powder is dissolved in water. In adult patients, two sachets of sodium picosulfate/magnesium citrate was at least as effective and well tolerated as oral magnesium citrate 17.7 or 35.4 g, or oral polyethylene glycol 236 g in adult patients undergoing a double-contrast barium enema procedure in three large, randomized, comparative clinical studies. In contrast, sodium picosulfate/magnesium citrate was less effective than a sodium phosphate enema preparation in two studies in patients undergoing flexible sigmoidoscopy. A similar number of patients receiving two sachets of sodium picosulfate/magnesium citrate or two 45 mL doses of oral sodium phosphate the day before a double-contrast barium enema procedure achieved satisfactory barium coating and none/minimal faecal residue in one study. However, the data from three of these studies should be interpreted with caution because the administrative regimens used differed from that recommended. Sodium picosulfate/magnesium citrate is also an effective and generally well tolerated colorectal cleansing agent in children and adolescents; the preparation was more effective than oral bisacodyl 0.01 or 0.02 g plus a sodium phosphate enema preparation in this population. Further research is thus required to accurately position sodium picosulfate/magnesium citrate and fully establish its efficacy and tolerability prior to various exploratory or surgical procedures. Nevertheless, oral sodium picosulfate/magnesium citrate provides a useful option in the preparation of the colon and rectum in adults, adolescents and children undergoing any diagnostic procedure (e.g. colonoscopy or x-ray examination) requiring a clean bowel and/or surgery. Oral sodium picosulfate/magnesium citrate acts locally in the colon as both a stimulant laxative, by increasing the frequency and the force of peristalsis (sodium picosulfate component), and an osmotic laxative, by retaining fluids in the colon (magnesium citrate component), to clear the colon and rectum of faecal contents. It is not absorbed in any detectable quantities. Sodium picosulfate is a prodrug: it is hydrolyzed by bacteria in the colon to the active metabolite 4,4'-dihydroxydiphenyl-(2-pyridyl)methane. Sodium picosulfate/magnesium citrate may be associated with a dehydrating effect, as evidenced by a reduction in bodyweight and increased haemoglobin levels; some at-risk patients may experience postural hypotension and older patients may require additional electrolytes. In three large (n >100), randomized, single-blind clinical studies, two sachets of oral sodium picosulfate/magnesium citrate was at least as effective as oral magnesium citrate 17.7 or 35.4 g, or oral polyethylene glycol 236 g as a colorectal cleansing agent in adult patients undergoing a double-contrast barium enema procedure. In contrast, sodium picosulfate/magnesium citrate was less effective than a sodium phosphate enema preparation in two studies in patients undergoing flexible sigmoidoscopy. A similar number of patients receiving two sachets of sodium picosulfate/magnesium citrate or two 45 mL doses of oral sodium phosphate the day before a double-contrast barium enema procedure achieved satisfactory barium coating and none/minimal faecal residue in one study. However, the data from three of these studies should be interpreted with caution because the administrative regimens used differed from that recommended. In children and adolescents, sodium picosulfate/magnesium citrate was significantly more effective as a colorectal cleansing agent than oral bisacodyl 0.01 or 0.02 g plus a sodium phosphate enema preparation in a randomized, single-blind study; dosages were adjusted for age in this study. Oral sodium picosulfate/magnesium citrate is generally well tolerated in adult patients undergoing various investigational colorectal procedures. Adverse events were generally mild to moderate in intensity and mainly gastrointestinal in nature (e.g. abdominal cramps/pain, nausea); other common treatment-emergent adverse events included disturbance of daily activity, headache and sleep disturbance. This combination is at least as well tolerated as oral sodium phosphate or oral polyethylene glycol, with moderate/severe nausea and vomiting occurring less frequently in sodium picosulfate/magnesium citrate recipients than in those receiving oral sodium phosphate, and abdominal bloating/pain and nausea developing less often with sodium picosulfate/magnesium citrate than polyethylene glycol therapy. The incidence of abdominal pain and sleep disturbance in sodium picosulfate/magnesium citrate versus oral magnesium citrate recipients was similar in one study, but significantly lower with sodium picosulfate/magnesium citrate in another. While the incidence of most adverse events was similar in recipients of sodium picosulfate/magnesium citrate and a sodium phosphate enema preparation, more patients receiving sodium picosulfate/magnesium citrate reported moderate/severe flatulence, incontinence and sleep disturbance, and more patients receiving the enema preparation reported rectal soreness. The tolerability profile of sodium picosulfate/magnesium citrate in patients aged >70 years is reportedly similar to that in patients aged <70 years. Abdominal pain also occurred less frequently with sodium picosulfate/magnesium citrate than with oral bisacodyl plus a sodium phosphate enema preparation in children and adolescents.

Introduction of an enhanced recovery protocol for radical cystectomy

OBJECTIVE

To describe and assess an enhanced recovery protocol (ERP) for the peri-operative management of patients undergoing radical cystectomy (RC), which was started at our institution on 1 October 2005, as RC is associated with increased morbidity and longer inpatient stays than other major urological procedures.

PATIENTS AND METHODS

An ERP was introduced in our institution that focused on reduced bowel preparation, and standardized feeding and analgesic regimens. In all, 112 consecutive patients were compared, i.e. 56 before implementing the ERP and 56 since introducing the ERP. The primary outcome measures were duration of total inpatient stay and interval from surgery to discharge, and the morbidity and mortality. Data were analysed retrospectively from cancer network and hospital records.

RESULTS

The demographics of the two groups showed no significant difference in age, gender distribution, American Society of Anesthesiologists grade, or type of urinary diversion. Re-admission, mortality and morbidity rates showed no statistically significant difference between the groups. The median (interquartile range) duration of hospital stay was 17 (15-23) days in the no-ERP group, and 13 (11-17) days in the ERP group (significantly different, P < 0.001, Wilcoxon rank-sum test). The median duration of recovery after RC was 15 (13-21) days in the no-ERP group and 12 (10-15) days in the ERP group (significantly different, P = 0.001, Wilcoxon rank-sum test).

CONCLUSION

The introduction of an ERP was associated with significantly reduced hospital stay, with no deleterious effect on morbidity or mortality.

Randomized clinical trial comparing sodium picosulfate with mannitol on the preparation FOR colonoscopy in hospitalized patients

BACKGROUND: The cleansing of the colon for a colonoscopy exam must be complete so as to allow the visualization and inspection of the intestinal lumen. The ideal cleansing agent should be easily administered, have a low cost, and minimum collateral effects. Sodium picosulfate together with the magnesium citrate is a cathartic stimulant and mannitol is an osmotic laxative, both usually used for this purpose. AIMS: Assess the colon cleanliness comparing the use of mannitol and sodium picosulfate as well as evaluate the level of patient satisfaction, the presence of foam, pain, and abdominal distension in hospitalized patients undergoing colonoscopy. METHODS: A prospective, randomized, single-blind study with 80 patients that compared two groups: mannitol (40) and sodium picosulfate (40). Both groups received the same dietary orientation. The study was approved by the hospital’s Ethics and Research Committee. The endoscopist was blind to the type of preparation. Outcomes evaluated: level of the colon’s cleanliness, patient’s satisfaction, the presence of foam, abdominal pain and distension, and the duration of the exam. The data was analyzed by means of the chi-squared test for proportions and Mann-Whitney for independent samples. RESULTS: There were no statistically significant differences between the groups in relation to the level of the colon’s cleanliness, patient’s satisfaction, the presence of foam, abdominal pain, and the duration of the exam. Fifteen percent of the exams of the mannitol group were interrupted while from the sodium picosulfate group it was 5%. The presence of foam was similar for both groups. The average duration for carrying out the exam was 28.44 minutes for the mannitol group and 35.59 minutes for the sodium picosulfate group. Abdominal distension was more frequent in the mannitol group. If they would have to do the same exam, the answer was that 80% said yes from the mannitol group and 92.5% from the sodium picosulfate group. CONCLUSION: The quality of the colon preparation, foam formation, exam duration, and the collateral effects (nauseas, vomiting, and abdominal pain) were similar in both kinds of preparations. Abdominal distension was greater in the mannitol group. Both methods of preparation were well accepted by the hospitalized patients.

Is mechanical bowel preparation necessary in patients undergoing cystectomy and urinary diversion?

OBJECTIVE

To compare the surgical outcome in patients with or with no bowel preparation before cystectomy and ileal conduit urinary diversion, specifically assessing local and systemic complications.

PATIENTS AND METHODS

All patients undergoing cystectomy and ileal conduit urinary diversion between January 1991 and December 1999 were assessed retrospectively. Twenty-two receive no bowel preparation (group 1) and were compared with 64 who had (group 2). Patients had similar demographic characteristics, stage and grade of tumour. Patients in group 2 received a standard 4-day bowel preparation and group 1 received no lavage or enemas. All patients underwent a standard iliac and obturator lymph node dissection, and cystoprostatectomy or anterior exenteration and ileal conduit urinary diversion. All patients received intraoperative metronidazole and gentamicin intravenously, and two further doses after surgery.

RESULTS

Deaths after surgery were comparable in the two groups (two in group 1 and four in group 2) and the incidence of wound infection was similar (three and seven, respectively). There were no significant differences between the respective groups for fistula and anastomotic dehiscence (two and six) or sepsis (three and six). Group 2 had a higher incidence of wound dehiscence (one) than in group 1 (none). The incidence of prolonged postoperative ileus was lower in group 1 (one vs 12), as was the length of hospital stay (31.6 days vs 22.8 days).

CONCLUSIONS

Bowel preparation had no advantage for the surgical outcome but it increased the length of hospital stay.

Review article: the therapy of constipation

Constipation is a common symptom that may be idiopathic or due to various identifiable disease processes. Laxatives are agents that add bulk to intestinal contents, that retain water within the bowel lumen by virtue of osmotic effects, or that stimulate intestinal secretion or motility, thereby increasing the frequency and ease of defecation. Drugs which improve constipation by stimulating gastrointestinal motility by direct actions on the enteric nervous system are under development. Other modalities used to treat constipation include biofeedback and surgery. Laxatives and lavage solutions are also used for colon preparation and evacuation of the bowels after toxic ingestions.

Clinical pharmacology and use of laxatives and lavage solutions

Laxatives and lavage solutions are used in the treatment of constipation and toxic ingestion and also for preparation of the colon before endoscopic or surgical procedures. Several different categories of agents are available for use. These include bulking agents, osmotic agents, secretagogues and agents with direct effects on epithelial nerve or smooth muscle cells, and lubricating agents. Each category has different pharmacologic effects, side effects, and clinical indications. This review summarizes current information about these agents.

Inpatient vs. outpatient bowel preparation for elective colorectal surgery

BACKGROUND

Recent pressures to decrease the cost of medical care have mandated preoperative outpatient bowel preparation (OBP) for elective colorectal surgery without any data documenting equivalent quality of care. This study examined the safety and efficacy of OBP compared with inpatient bowel preparation (IBP).

METHODS

Records of all patients who underwent OBP for elective colorectal resection since the inception of the OBP program from July 1993 to June 1994 were compared with records of all patients who received IBP for elective procedures from January to June 1993.

RESULTS

The two groups, 90 patients who underwent OBP and 98 patients who had IBP, were well matched for age, sex, diagnosis, and operations performed. The OBP group had a shorter length of hospital stay (median, 7 vs. 9 days; P < 0.0001; chi-squared analysis), whereas the complication rate was similar (19 percent in the OBP group vs. 18 percent in the IBP group), including infectious complications (10 percent in the OBP group vs. 7 percent in the IBP group). Although operating time was similar (mean, 199 vs. 213 minutes) and estimated blood loss (mean, 528 vs. 536 ml), the OBP group had significantly higher perioperative fluid requirements: intraoperative fluids (median, 4300 vs. 3700 ml; P < 0.05; Student's t-test), intraoperative colloid administration (48 vs. 29 percent; P < 0.0002; chi-squared), 24-hour postoperative fluids (3224 vs. 2700 ml; P < 0.0001; Student's t-test), and postoperative fluid challenges (50 vs. 20 percent; P < 0.0001; chi-squared analysis).

CONCLUSION

Outpatient bowel preparation for elective colorectal surgery is safe and effective. It offers shorter hospital stay, and, therefore, potentially reduces medical care cost. Patients with multiple medical problems may not tolerate extensive fluid shifts; therefore, other preoperative arrangements, such as inpatient or outpatient intravenous fluid therapy, need to be considered to minimize complications that may outweigh potential cost savings.