Pharmacologically Initiated Defecation for Persons With Spinal Cord Injury: Effectiveness of Three Agents

J. Glen House, MD, Steven A. Stiens, MD

Objective: To compare the effectiveness of hydrogenated vegetable oil-based bisacodyl (HVB) suppositories, polyethylene glycol-based bisocodyl (PGB) suppositories, and polyethylene glycol- based, glycerine, docusate sodium mini-enemas (TVC) in subjects with upper motor neuron spinal cord lesions.

Study Design: Prospective randomized double blind. Fifteen subjects received one of three HVB and 3 PGB suppositories in randomized sequence for each of six scheduled bowel care sessions. Additionally, 10 subjects received 3 TVC. The analysis used time events that divided the bowel sessions into intervals. The analysis also compared digital simulations, incontinence, and quantity of stool. Wilcoxon rank sum tests and paired t tests were used to compare the means of intervals during bowel care initiated by HVB, PGB, and TVC.

Results: (means in minutes and p values): Time to Flatus - HVB,32; PGB, 15; TVC, 15; p <.026, HVB-PGB; p < .983, PGB-TVC; Flatus to Stool Flow - HVB, 6.7 ; PGB 5.5; TVC 3.9 p < .672, HVB - PGB; p < .068, PGB-TVC; Defecation Period - HVB , 36; PGB, 20; TVC, 17; p < .037, HVB - PGB; p < .479, PGB - TVC; Wait Until Transfer - HVB, 10.9; PGB, 10.7; TVC, 7.4; p < .932, HVB - PGB; p < .043, PGB - TVC; Total Time for the bowel program -HVB, 74.5; PGB, 43; TVC, 37; p < .010, HVB - PGB; p < .458, PGB - TVC; percent incidence of incontinence between bowel care sessions - HVB, .067; PGB, .067; TVC, .033; p < 1.0, HBV-PGB; p < .678, PGB-TVC; amount of stool produced - HVB, 3.30; PGB, 3.49; TVC, 3.38; p < .276, HVB-PGB; p < .630, PGB-TVC; average number of digital stimulations per bowel care procedure -HVB, 4.4; PGB, 4.1; TVC, 3.8; p < .411, HVB-PGB; p < .293, PGB-TVC; time per digital stimulation in seconds - HVB 107; PGB, 40; TVC, 83; p < .149, HVB-PGB; p < .352 PGB-TVC; and the total time, in minutes spent performing digital stimulation during bowel care -HVB, 10.0; PGB, 2.7; TVC, 5.9; p <.151, HVB-PGB; p <.325, PGB-TVC.

Conclusion: Bowel care took less time when initiated with the PGB bisacodyl or TVC mini-enema as compared with the HVB bisacodyl suppository (p < .01)

This is a US government work. There are no resrtictions on its use.

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 From the Department of Physical Medicine and Rehabilitation Baylor College of Medicine, Houston TX. and University of Washington School  of Medicine Seattle (Dr. House) and the Spinal Cord Injury Unit, Veterans Administration Puget Sound Health Care System, Seattle Division, and Department of Rehabilitation Medicine, University of Washington, Seattle (Dr.Stiens).

Submitted for publication November 6,1997. Accepted in revised form January29,1997 No commercial party having direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated.

Reprint requests to Steven A. Stiens MD. MS. Mail Location 356-490 Health Sciences Building BB938. 1959 NE Pacific, Seattle, WA. 98195. This is a US Government work. There are no restrictions on its use. 0003-9993/97/7810-4263 $0.00/0

Spinal Cord Injury (SCI) results in many impairments that profoundly affect a person's life. Neurongenic bowel dysfunction is one of the most significant complications that affects the quality of life. Furthermore, bowel care often occupies a relatively large portion of the day for a person with SCI. More than 20% of persons with SCI report difficulty with evacuation of their bowels. Bowel care procedures can require up to 3 hours for completion, and yet yield insufficient results. Complications related to bowel dysfunctioncan lead to patient morbidity and require surgical intervention. Fecal impaction is the most common colonic complication after SCI, but complications also include  intractable constipation and overflow incontinence. Bowel dysfunction continues to be a major cause of autonomic dysreflexia after SCI. Chronic complications, such as diverticuli, develop more rapidly after SCI but rarely occur before 5 years after injury and are assumed to be acquired. It has been suggested that appropriate bowel program management to prevent chronic rectal overdistension may postponeor prevent these complications. After SCI, volitional defecation is disrupted and a bowel program that includes scheduled bowel care sessions is often required to achieve predictable defecation, continence of stool, and prevention of complications. Several techniques are used to initiate defecation, such as rectal insertion of suppositories, mini-enemas, enemas, and digital stimulation.                                             Individuals with SCI occasionally attempt to augment theirbowel programs with laxatives. Oral laxatives have been categorized into four groups; dietary fiber and bulking agents, osmotic laxatives, stimulant laxatives and stool softeners. Bulking agents (bran, wheat husk, etc) cause fluid retention within the colon and increase bulk and stool softeners, leading to facilitated intestinal transit. Osmotic laxatives (mannitol, sorbitol, lactulose, magnesium citrate) retain water in the feces to produce a consistency that facilitates transit. Stimulant laxatives (bisacodyl, phennolphthanalein, glycerol) act at the intestinal mucosa and stimulate intestinal motility, which decreases the time available for salt and water absorption, further decreasing transit time. Stool softeners (docusate sodium, etc.) directly decrease stool firmness, reducing constipation.Suppositories frequently contain a contact stimulant laxative and are administrated to enhance colonic peristalsis. Currently, bisacodyl  is the active ingredients in most commonly used in bowel evacuation suppositories. Bisacodyl (bis (p-acetoxyphenal)-2-pyridyl- methane), is a compound that is practically insoluble in water and alkaline solutions. This agent is very poorly absorbed by the colon and acts directly at the mucosa to stimulate the sensory nerves, producing a parasympathetic relex response of increased peristalic contractions throughtout the large intestine. A rectally-administered water suspension of bisacodyl produces increased peristaltic activity in 3 minutes. Bisacodyl also stimulates fluid and electrolyte accumulation within the colon, adding laxative affects.                                                               The most commonly used laxative suppositories contain 10mg bisacodyl powder distributed within a hydrogenated vegetable-oil based (HVB). A considerably long waiting period has been observed after insertion of the HVB suppository until initial results of flatus and first stool flow. Studies have found that up to 20% of patients require at least 45 minutes from HVB insertion to first stool flow and may experience excessive mucus production after