Introduction of New Hypo-osmolar ORS into Routine Use in the Management of Diarrhoeal Disease

Oral rehydration therapy (ORT) using a mixture of salt, sugar, and water in the treatment of diarrhoeal disease has been recognized as an important discovery in medical science; because the therapy is simple, cheep and saves millions of lives. In 1976, WHO and UNICEF recommended the present oral rehydration solution (ORS) formulation (sodium chloride or common salt 3.5 g, sodium bicarbonate 2.5 g, potassium chloride salt 1.5 g, and glucose 20 g/litre with a osmolarity of 311 mosmol/litre) for use in all types of diarrhoea including cholera and in all age groups. Although this ORS solution is effective and safe, it has some limitations such as, (a) it does not reduce diarrhoea stool volume and duration, (b) parents concern is to stop diarrhoea, not to correct dehydration. These limitations have encouraged the researchers to find out an improved ORS formulation. For the last 20 years, many animal and clinical studies have examined different compositions of ORS and evaluated their efficacy and safety. On 18^th July 2001, WHO and UNICEF convened an expert committee meeting held at UNICEF headquarter, New York to review the results of all studies done so far. The committee has recommended a revised composition of ORS (sodium chloride 2.6 g, trisodium citrate 2.9 g, potassium chloride 1.5 g, glucose 13.5 g per litre with a osmolarity of 245 mosmol/litre) as a replacement of the previously recommended ORS for use in all causes of diarrhoea in all age groups. This composition was recommended because this ORS was found to: (a)reduce unscheduled intravenous fluid requirement (ORS failure), (b)reduce stool output, and (c) reduce vomiting. But this ORS was found to be associated with significantly more asymptomatic hyponatraemia in adult patients with cholera. Therefore, the committee also recommended a phase IV clinical trial (post-marketing surveillance study) when it is first introduced for routine use to identify any symptomatic (e.g. convulsion) hyponatraemia (serum sodium level below normal range).

As ICDDR,B is the largest diarrhoea treatment centre, we have initiated a surveillance protocol since November 2002 in Dhaka Hospital and from February 2003 in Matlab Hospital. All patients that stay in the hospital for >8 hrs are under the surveillance protocol. Patients developing convulsion during the treatment in the hospital and taking ORS are thoroughly investigated clinically and with laboratory investigations. Preliminary results show that no adult patients have experienced any convulsion associated with hyponatraemia. By the end of the study in February 2004, we will be able to report the final results.