Recent Developments in Oral Replacement of Fluid and Electrolyte Losses

Oral rehydration therapy (ORT), using a solution of glucose and three salts (ORS) is an elegant and deceptively simple therapeutic technology, to treat or prevent dehydration from diarrhea, that stood the test of time over the past 25 years of use. It contributed substantially to the dramatic global reduction in mortality from diarrheal diseases during this period (1). However, its use does not make diarrhea any less severe or stop it sooner (2), which encourages large-scale use of ineffective and sometimes harmful medicines. Based on a conceptual framework (3,4) WHO in the early 80's launched studies to develop a more absorption efficient improved ORS formula which could make diarrhea less severe and/or have other clinical benefits. During the past 20 years many studies were carried out to develop an improved ORS and several reviews have summarized the results (5-8). Two approaches were used, (i) modifying the amount and type of organic carriers used in ORS to promote better absorption of salt and water (e.g., combining glucose or maltodextrins with amino acids like glycine or 1-alanine or 1-glutamine), and (ii) reducing the osmolarity of ORS solution to enhance absorption by osmotic flow of fluids and avoid the adverse osmotic penalty due to hyperosmolarity (e.g., by reducing the concentration of glucose and salts or by replacing glucose with a complex carbohydrate).