The present study investigated the efficacy and tolerability of polyethylene glycol/ electrolyte solution therapy in patients with fecal impaction and severe constipation. 

It included 16 inpatients (aged 26 to 87 years) and 14 outpatients (aged 17 to 61 years) with a history of chronic constipation, absent bowel motions for five or more days, and had faecal loading confirmed by clinical examination. It excluded completely bedridden patients or those with suspected intestinal obstruction or severe inflammatory bowel disease. 

The study prescribed each daily treatment consisting of 1 liter of Movicol, administered as two 500ml portions to be taken within 4 to 6 hours. 

It defined Relief of an impaction as a passage of a large or moderate stool volume and the disappearance of previously palpable fecal masses in the abdomen and/or rectum. 

The study observed complete resolution of constipation or impaction in 13 patients after one day, 11 more after two days, and one more after three days. It also saw significant improvement in all other patients. The only symptom observed to be significantly associated with the treatment was abdominal rumbling, evidence of the drug′s action in stimulating colonic motility. 

Thus the study concluded that Movicol, when given as a treatment dose equivalent to eight sachets (1 liter) daily for up to 3 days, is a highly effective and acceptable oral therapy for fecal impaction. 

Source: Culbert P, Gillett H, Ferguson A. Highly effective oral therapy polyethylene glycol/electrolyte solution for faecal impaction and severe constipation. Clin Drug Invest. 1998;16(5):355-60.