Oral rehydration solution for diarrhea

Newer polymer-based formulations of oral rehydration solution given to treat diarrhoea may offer some benefits over older sugar-salt formulations.

But, say Cochrane researchers who carried out a review of the available evidence, more research is required to establish the best treatment option.

Acute diarrhoea is a major cause of childhood death in developing countries. Children are treated with oral rehydration solution (ORS), which is given to help replace lost fluid and prevent further dehydration. While ORS formulations have traditionally contained sugar and salt, new formulations have been tested that replace the sugar with sugar-containing polymers from rice, wheat, sorghum, and maize.

One problem with sugar-based ORS solutions is that the sugar actively draws water from the body, making the diarrhoea worse. The sugar is also present for only a short time before it is used or voided. In contrast, the polymers release sugar slowly, lessening its ability to cause dehydration, and providing a long, low-level source of energy - a so-called 'glucose-battery'.

The review focused on 27 trials in children, five in adults and two in both. Together they included 4,214 participants and indicated that polymer-based ORS reduced the time that cholera patients suffered from diarrhoea. Polymer-based ORS also decreased the need to give patients intravenous fluid compared to previous, higher concentration sugar-salt solutions, but evidence was limited for the comparison with less concentrated salt solutions that are currently recommended.

"More trials comparing polymer-based ORS formulations to the current best agreed formula are needed," says lead researcher Germana Gregorio, who works at the Department of Pediatrics of the Philippine General Hospital at the University of the Philippines.

As Gregorio points out, however, polymer based formulations are less practical to prepare. "Glucose-based ORS requires only mixing of the contents of a sachet with boiled water, whereas rice, wheat, maize and potatoes are more tedious to prepare," she says. "And in humid countries they have to be consumed in a few hours to avoid bacterial contamination."