Kienzle-Horn, S., Vix, J.M., Schuitjt, C., Peil, H., Jordan, C.C., & Kamm, M.A. (2007). Comparison of bisacodyl and sodium picosulfate in the treatment of chronic constipation. Current Medical Research and Opinion, 23, 691–699.

To compare the safety and efficacy of bisacodyl and sodium picosulphate.

Patients received 5 to 10 mg of bisacodyl sugar-coated tablets or sodium picosulphate drops daily over four weeks. The study schedule included four visits: an initial screening visit followed by a seven-day baseline period, a randomization visit (1:1 basis) and two follow-up visits on days 15 and 29.

• The study reported on a total sample of 144 patients with chronic constipation, defined as fewer than three stools per week for at least six months, or pain or straining with bowel movements for six months.
• Patients were aged older than 18 years (range 23–64).
• The study comprised 70 patients in the bisacodyl group ( 21 men and 49 women) and 74 patients in the sodium picosulphate group (19 men and 55 women).
• Patients were included in the study if they were aged 18 years or older and had a confirmed diagnosis of chronic constipation. 
• Patients were excluded if they had a history of organic disease of the colon, ileus, any acute surgical abdominal conditions, organic diseases of the rectum and anus, presence of active gastrointestinal disease, obstruction or dehydration, ingestion of any drug affecting gastrointestinal motility, hypersensitivity to triarylmethane compounds, and recent use (within the past seven days) of bisacodyl or sodium picosulphate.

15 centers (outpatient clinics and specialist gastroenterology units) in Germany

This was a phase IV, open-label, randomized, parallel group study.

• Primary efficacy was assessed as number of bowel movements per day and daily stool consistency using a five-point scale (from liquid to hard).
• Secondary efficacy was assessed as degree of straining using a scale from 0 (absent) to 5 (severe) and physician global efficacy assessment.
• Safety assessments included adverse-event monitoring, tolerability, and changes in laboratory parameters.
• Physical examination and blood samples were completed on days 1, 15, and 29.

• Demographic distribution and baseline characteristics of the two treatment groups were similar.
• Stool frequency and consistency and occurrence of straining after 14 and 28 days was significantly improved for both groups compared to baseline (p < 0.0001).
• Physician global rating improved in 74.6% of patients in the bisacodyl group and 79.2% of patients in the sodium picosulphate group.

Bisacodyl and sodium picosulphate are equally tolerated and effective in the treatment of chronic constipation.

• The study lacked a placebo group.
• Secondary efficacy parameters were subjective, but generally accepted.
• The study evaluated safety over 28 days and did not address potential long-term changes in gastrointestinal mucosa.
• No patients with cancer or opioid-induced constipation were included in the study.