As per current WHO recommendations adopted in India, the low-osmolarity oral rehydration solution used for diarrhoea has a total osmolarity of:

• A 245 mOsm/L with sodium 75 mmol/L ✓
• B 311 mOsm/L with sodium 90 mmol/L
• C 200 mOsm/L with sodium 50 mmol/L
• D 280 mOsm/L with sodium 110 mmol/L

Explanation

WHO reduced osmolarity ORS contains sodium 75, chloride 65, potassium 20, citrate 10, glucose 75 mmol/L, giving total osmolarity of 245 mOsm/L. It reduces stool output, vomiting and need for intravenous fluids compared with the older full-strength formula of 311 mOsm/L and sodium 90 mmol/L. The other figures do not correspond to any WHO formulation; 200 mOsm/L would be dangerously hyponatraemic for standard use.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.