0016-5107/91/3705-0547$03.00GASTROINTESTINAL ENDOSCOPYCopyright © 1991 by the American Society for Gastrointestinal Endoscopy

Addition of senna improves colonoscopypreparation with lavage: a prospectiverandomized trial

D. J. Ziegenhagen, MD, E. Zehnter, MDW. Tacke, MD, W. Kruis, MD

Cologne, Germany

Attempts have been made to further improve the widely performed colonoscopypreparation with lavage. In a prospective study, 120 outpatients and inpatientsscheduled for total colonoscopy were randomized to two preparatory regimens.The day before endoscopy either extractum sennae (N = 60) or a placebo solution(N = 60) was given. Just before examination all patients underwent whole gutirrigation with a polyethylene glycol electrolyte lavage solution (PEG-ELS).Adequacy of preparation, patient tolerance, and the necessary amount of PEG­ELS were assessed. Physician assessment of colon cleansing showed superiorityin the group with additional laxative. The colon was free of solid debris in 66.7%of patients after PEG-ELS and in 90% after senna/PEG-ELS administration (p <0.01). Patient tolerance was similar in both groups with 86.7% vs. 83.3% ofsubjects rating the preparation as tolerable. Severe adverse events were notobserved. In the senna/PEG-ELS group, significantly less (p < 0.05) lavage fluidwas needed. We conclude that the combination of senna and PEG-ELS is moreeffective than PEG-ELS in cleansing the colon for colonoscopy. (GastrointestEndosc 1991;37:547-549)

The colon must be free of feces before examinationby colonoscopy or barium enema. This purpose can beachieved best by whole gut irrigation with large vol­umes of fluid. Formerly, this procedure was compli­cated by disturbances of electrolyte and fluid balance,and by the generation of combustible gases in thecolon.!

These drawbacks were overcome by the introduc­tion of a polyethylene glycol containing electrolyte­balanced solution.2 It was shown that lavage with thissolution is associated with negligible salt and waterabsorption.3 Its superiority to formerly used standardcolon preparations in terms of efficacy and patientacceptance has been repeatedly reported.4

-8 However,

with polyethylene glycol electrolyte lavage solution(PEG-ELS) we still noted a considerable number ofinsufficient preparation results either leading to sub­optimal visualization of small lesions or requiring

Received January 31, 1991. For revision March 19, 1991. AcceptedJune 17, 1991.From the Department of Medicine I, Gastroenterology Unit, Univer­sity of Cologne, Cologne, Germany. Reprint requests: Dieter J. Zie­genhagen, MD, Klinik I fuer Innere Medizin, Josef-Stelzmann­Strasse 9, W-5000 Koeln 41, Germany.

VOLUME 37, NO.5, 1991

repetition of the procedure. On the other hand, PEG­ELS lavage may require fairly large volumes to beingested with the disadvantages of decreased patientacceptance, longer preparation times, and highercosts.9 Therefore, we report here the results of a pro­spective randomized blinded trial to determine theeffectiveness of supplemental extractum sennae incolon preparation with PEG-ELS.

PATIENTS AND METHODS

Patient selection

Adult patients undergoing colonoscopy for routine clinicalindications were included in the study and randomly as­signed to one of two cleansing regimens. Exclusion criteriawere: pregnancy, prior alimentary tract surgery, ileus andsuspected bowel obstruction, symptoms of gastroparesis,refusal of informed consent, and doubts about the patient'sability to perform the preparation carefully or to describethe experience with it. One hundred twenty consecutivepatients fulfilling these criteria were enrolled in the study.

Colonic cleansing procedure

Patients were advised to reduce food intake and to avoidprotein-rich or flatulent nutrients 2 days before examina-

547

Table 1.Clinical characteristics of study population

Table 3 shows the comparative results of patienttolerance and the frequency of side effects. Globaltolerance was assessed as good by a large majority ofboth groups (PEG-ELS, 86.7% vs. senna/PEG-ELS,83.3%). Adverse effects were reported by 15 (30%)patients in the PEG-ELS and 16 (31.7%) in the senna/PEG-ELS group.

Leading symptoms were abdominal fullness andcramping. In the senna/PEG-ELS group complaints

PEG-ELS Senna + PEG-ELS(N = 60) (N = 60)

tion. The day before colonoscopy only clear liquids wereallowed, and at 3 p.m. group A drank 75 ml of a placebosolution and group B received 75 ml of a solution standard­ized to 150 mg of sennosides A and B (X-Prep@; Mundi­pharma GmbH, Limburg, Germany). For the rest of the dayboth groups were advised to drink 2 liters of non-sparklingmineral water.

The following day both groups received PEG-ELS beforecolonoscopy. The lavage was given by mouth or via a naso­gastric tube if this was already inserted for other purposesor if vomiting occurred. Lavage was ingested at a rate of 1to 2 liters/hour until rectal effluent became clear.

Patient tolerance and measurements

Body weight and age of patients, quantity, and durationof ingestion of lavage solution were recorded. General pa­tient tolerance of cleansing was assessed just before colon­oscopy and was graded as follows: 1 (good), 2 (fair), and 3(bad). Patients were asked for bothersome side effects in afree form.

Adequacy of preparation

Blinded to the preparation given, the attending gastroen­terologist graded the adequacy of preparation according tothe following scale: 1 (excellent), dry colon or colorless fluidonly; 2 (good), fluid residue in feces-like color; 3 (sufficient),minimal solid fecal residue; and 4 (poor), notable amount ofsolid fecal residue.

Age (yr)MeanRange

Weight (kg)MeanRange

Sex (M/F)Outpatients/inpatientsIndications

PolypMassBleedingInflammatory bowel diseaseOthers

51.821-83

69.449-10630/3045/15

21 (35.0%)12 (20.0%)16 (26.7%)7 (11.7%)4 (6.7%)

50.518-77

71.947-11332/2848/12

24 (40.0%)9 (15.0%)

17 (28.3%)8 (13.3%)2 (3.3%)

Table 3.Patient tolerance responses and side effects

PEG-ELS Senna/PEG-ELS(N = 60) (N = 60)

,t possible.

" Hemorrhoidal pain.b Oral mucosal irritation., More than one complaint pel

32 (53.3%)22 (36.7%)6 (10.0%)o (0.0%)

54 (90.0%)"

50 (83.3%)7 (11.7%)3 (5.0%)

10 (16.7%)9 (15.0%)3 (5.0%)1 (1.7%)1 (1.7%)b

16 (31.7%)

Senna/PEG-ELS(N = 60)

PEG-ELS(N = 60)

27 (45.0%)13 (21.7%)18 (30.0%)2 (3.3%)

40 (66.7%)

52 (86.7%)7 (11.7%)1 (1.7%)

12 (20.0%)7 (11.7%)7 (11.7%)2 (3.3%)1 (1.7%)"

15 (30.0%)

I-Excellent2-Good3-Sufficient4-Poor1 + 2-Free of solid debris

"p < 0.01.

Table 2.Adequacy of preparation

Global toleranceGoodFairBad

Adverse reactionsFullnessCrampingNausea/vomitingCirculatory reactionsOthers

Total'

RESULTS

All of the 120 patients randomized and enrolled inthe study completed the scheduled procedure. Therewere no statistically significant differences among thetwo groups in age, weight, sex, and inpatient to out­patient ratios and in indications for colonoscopy (Ta­ble 1). The mean volume of solution ingested wassignificantly lower (p < 0.02) in the laxative additiongroup (PEG-ELS, 3.84 liters ± 1.38 SD; senna/PEG­ELS, 3.33 liters ± 1.18 SD). Mean ingestion timesshowed no significant difference (PEG-ELS, 2.1 hours± 0.8 SD; senna/PEG-ELS, 1.9 hours ± 0.8 SD).

The scoring results of colon cleansing are shown inTable 2. The ratings 1 and 2, representing completeremoval of solid residue from the colon, were achievedwith lavage only in 66.7% of patients and with thecombination of senna and lavage in 90% of patients.Inadequate cleansing preventing reliable examinationof the colon was observed in two patients (3.3%) ofthe PEG-ELS group and in none of the senna/PEG­ELS group.

Statistical analysis

Group values for age, weight, indications for the proce­dure, and lavage volume were compared by unpaired Stu­dent's t test. Comparisons for sex and inpatient to outpatientratios, adequacy of preparation, and patient tolerance weredone by the chi-square method. p < 0.05 were consideredsignificant.

548 GASTROINTESTINAL ENDOSCOPY

were predominantly associated with lavage. Only fourpatients reported abdominal cramping after sennaadministration on the day before colonoscopy. Globaltolerance assessment, total numbers of subjects ex­periencing symptoms, and proportions of single com­plaints were not significantly different.

DISCUSSION

Although superior to former standard preparationregimens,4-8 PEG-ELS in some patients still leavessmall amounts of residual stool, primarily in the rightcolon. The 33.3% incidence of fecal residue found inour study is similar to others reporting 39%10 or 42%.7But it must be questioned if even small amounts ofresidual stool in the colon are acceptable. For example,considering that colonic angiodysplasias are often lessthan 0.5 em in size,l1, 12 it seems reasonable to makeefforts to produce as complete a view of mucosalsurfaces as possible. Although we had the impressionthat such minor lesions could have been missed in thecases with minimal fecal residue (score 3, sufficient),it remains very difficult to prove its relevance forclinical outcome.

Thus, endoscopists have to decide whether additionof senna is useful depending on the indication for aparticular examination. Nevertheless, we consider itan important improvement that in 90% of cases in thelaxative supplement group complete removal of fecesfrom the colon was achieved.

Our results support previous reports on safety andgenerally good patient acceptance of colonoscopypreparation with lavage.4-7,10,13 The incidence of re­ported side effects is obviously lower when patientsare interviewed in a free form instead of using aprepared questionnaire for expected symptoms.13 Asthe latter approach contains a tendency to over­estimate the relevance of symptoms for individualpatients, we consider the global tolerance assessmentto be a valuable parameter for clinical practicabilityof a routine procedure like colon preparation. Thisassumption is supported by the fact that nearly halfof the patients reporting side effects neverthelessscored the global tolerance as good.

Analyzing the individual symptoms in both groups,these were more closely related to the ingestion ofPEG-ELS than to the senna supplement. Althoughnot statistically significant, the higher frequency ofnausea and vomiting in the PEG-ELS group may beattributable to the significantly larger amount of la­vage solution needed without laxative addition.

Sennosides are effective mainly by an anti-absorp­tive-secretagogue mechanism,14 but in humans alsocolonic motility is considerably enhanced.15 As sen-

VOLUME 37, NO.5, 1991

nosides are pro-drugs which release their laxative­active metabolites only after bacterial degradation inthe colon,16 their maximal laxative effect is not exertedbefore 6 hours after oral ingestion.17 Because of thispharmacokinetic property, a sufficient interval (in ourstudy about 16 hours) between laxative applicationand start of lavage seems important. If appropriatelyapplied, the combination of PEG-ELS with other lax­atives, e.g., bisacodyl (own data, unpublished), is asimilarly effective, safe, and well-tolerated method foroptimal colon preparation.

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