India adopted the reduced osmolarity oral rehydration solution (ORS) recommended by WHO. Compared with the earlier standard ORS, the key change in the reduced osmolarity formulation is:
- A Total osmolarity lowered to 245 mOsm/L with sodium reduced to 75 mmol/L ✓
- B Glucose content was doubled to speed water absorption
- C Total osmolarity increased to about 310 mOsm/L
- D Potassium was removed to prevent hyperkalaemia
Correct answer: A. Total osmolarity lowered to 245 mOsm/L with sodium reduced to 75 mmol/L
Explanation
The reduced osmolarity ORS contains sodium 75 mmol/L, chloride 65, glucose 75, potassium 20, citrate 10, giving a total osmolarity of 245 mOsm/L compared with 311 in the old formula. It reduces stool output, vomiting, and the need for intravenous fluids, and lowers the risk of hypernatraemia seen with the older high-sodium solution. Glucose concentration is unchanged in principle, remaining equimolar with sodium to drive cotransport.
Reference: Park's Textbook of Preventive and Social Medicine, 26th ed.
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