High-Dose Senna Compared with Conventional PEG-ES Lavage as Bowel Preparation for Elective Colonoscopy: A Prospective, Randomized, Investigator-Blinded Trial

OBJECTIVE To compare the efficacy and patient acceptance of an oral high dose of senna to conventional polyethylene glycol-electrolyte lavage solution (PEG-ES) in adults undergoing elective colonoscopy. METHODS Consecutive outpatients referred for elective colonoscopy were prospectively randomly assigned to receive, the day before the procedure, either 24 tablets of 12 mg senna, divided into two doses at 1 p.m. and 9 p.m. (senna group, n = 191), or standard 4-L PEG-ES (PEG-ES group, n =192). The overall quality of colon cleansing (primary outcome measure) and cleansing in the right colon were evaluated using the Aronchick scoring scale (1 = excellent to 4 = inadequate) by the investigator/endoscopist who was blinded to the treatment assignment. Patient acceptance and the safety of the preparation were assessed by a nurse, using a structured questionnaire covering compliance with the dosing, overall tolerance of the preparation (1 = none or mild discomfort to 4 = severely distressing), and adverse events. RESULTS The quality of colon cleansing, overall tolerance of the preparation, and compliance were significantly better with senna; overall cleansing was excellent or good in 90.6% of patients in the senna group and in 79.7% in the PEG-ES group (p = 0.003). The percentage of procedures rescheduled because of insufficient colon cleansing was 7.3% in the PEG-ES group and 2.6% in the senna group (p = 0.035). Multivariate logistic regression modeling showed the PEG-ES preparation as negative independent predictor of unsuccessful bowel cleansing. The incidence of adverse reactions was similar in the two groups; patients who received senna experienced significantly less nausea and vomiting, but more abdominal pain. CONCLUSIONS An oral high dose of senna is a valid alternative to standard PEG-ES for outpatient colonoscopy preparation.