Polyethylene Glycol for Chronic Constipation

Six months of treatment provided significant symptom relief, compared with placebo.

Polyethylene glycol (PEG) 3350 (MiraLax and others) is an osmotic laxative approved for short-term treatment of constipation. In this multicenter industry-sponsored study, researchers assessed the use of PEG for longer-term treatment of constipation.

The study included 304 patients (mean age, 53; 85% women) with chronic constipation, as defined by standardized criteria; the mean duration of constipation was 23 years. The patients were randomized to receive either once-daily PEG (a 17-g packet mixed with 8 oz of liquid) or placebo. During 6 months of treatment, the primary efficacy endpoint (at least 3 satisfactory bowel movements per week, without use of rescue laxative, for at least half of treatment weeks) was reached by 52% of PEG recipients and 11% of placebo recipients — a highly significant difference. Nearly all secondary endpoints also favored the PEG group decisively. Side effects included abdominal distention and diarrhea; no clinically significant laboratory abnormalities were noted.

Comment: Polyethylene glycol, prescribed for up to 6 months at the dose used in this trial, appears to be safe and reasonably effective for adults with chronic constipation. Note that the patients in this trial were generally healthy, had no evidence of organic bowel disorders, and were not taking medications known to cause constipation.

— Allan S. Brett, MD

Published in Journal Watch General Medicine July 12, 2007

Citation(s):
DiPalma JA et al. A randomized, multicenter, placebo-controlled trial of polyethylene glycol laxative for chronic treatment of chronic constipation. Am J Gastroenterol 2007 Jul; 102:1436-4