PEG vs. sennosides for opioid-induced constipation in cancer care

This randomized double-blind, double-dummy, 2-treatment, 2-period crossover study aimed to compare the efficacy and tolerability of polyethylene glycol (PEG) and sennosides in ambulatory cancer patients with opioid-induced constipation.

Outpatients ≥ 18 years old with cancer, at risk of or already experiencing opioid-induced constipation, were randomly assigned to begin a standard bowel protocol of escalating doses of sennosides or PEG, plus a dummy preparation. After 3 weeks, the patients switched to the alternate active product and dummy preparation. Constipation was assessed using the revised Victoria Bowel Performance Scale (rBPS) at the end of each of the 2 consecutive 21-day study periods for the number of days with a satisfactory bowel movement, the time in days to goal rBPS (G), and the treatment preference of each patient.

Seventy patients were recruited, with 42 completing their first treatment period and 28 completing both treatment periods. For the typical patient, the expected number of days with a satisfactory bowel movement per days of treatment was found to be 1.21 times higher on PEG than on sennosides in a particular period (95% credible interval 0.96 to 1.55). Patients taking PEG were 1.47 times more likely to reach a rBPS of G before patients taking sennosides in the first period (95% confidence interval 0.74 to 2.94). There was no evidence of a difference in patient preference between laxatives.

Our study found weak evidence that PEG is superior to sennosides with respect to overall effectiveness in cancer patients with opioid-induced constipation.