Role for carbon dioxide- releasing suppositories in the treatment of chronic functional constipation. A double-blind, randomised, placebo-controlled trial

Objective: Treatment of chronic functional constipation is difficult. Both oral and topical laxatives may fail to adequately relieve symptoms, and there is risk of adverse effects such as functional or structural changes in the intestine, together with electrolyte disturbances. The aim of this study was to evaluate the efficacy and safety of a suppository that combines sodium bicarbonate and potassium bitartrate in a polyethylene glycol base to generate approximately 175mL of carbon dioxide (CO2). This release distends the rectal ampulla, thereby stimulating peristalsis and a subsequent bowel movement. Patients and methods: This was a prospective, crossover, double-blind, randomised, placebo-controlled, sequential study of outpatients with chronic functional constipation. Each patient received two suppositories of identical appearance, containing active drug or placebo. The sequence of active drug-placebo (sequence 1) or placebo-active drug (sequence 2) was randomised in groups of eight. The second suppository was taken 7 days after the first. The following parameters were evaluated and scored: evacuation time, type of evacuation, feeling of emptying of the rectal ampulla, stool characteristics, anal complaints, abdominal pain and overall patient assessment. Results: A total of 29 patients entered the study. According to a restricted sequential plan, a statistical significance (p < 0.05) in favour of the active drug was reached after 26 patients. A positive response within 30 minutes of introduction of the suppository occurred in 51.7% and 6.9% of patients treated with the active drug and placebo, respectively (p = 0.0003). Normal evacuation occurred in 65.5% and 24.1% of patients treated with the active drug and placebo, respectively (p = 0.004). Normal stool consistency was found in 44.8% and 7.2% of patients treated with the active drug and placebo, respectively (p = 0.04). Patient assessment of treatment as satisfactory occurred in 51.7% and 20.7% of subjects treated with the active drug and placebo, respectively (p = 0.029). Only a trend in favour of the active drug was observed with regard to feeling of incomplete evacuation, and active drug was comparable to placebo with regard to anal and abdominal tolerability. Conclusion: The CO2-releasing suppository may represent an alternative to rectal laxatives for the relief of chronic functional constipation. The data obtained in this study indicate that CO 2-releasing suppositories may be usefully and safely employed in the treatment of patients at risk for electrolyte disorders such as the elderly or patients with renal or cardiovascular disorders.