The WHO reduced-osmolarity oral rehydration solution currently recommended for cholera and acute watery diarrhoea differs from the earlier standard ORS mainly in that it contains:

• A Higher glucose concentration of 111 mmol/L
• B Higher osmolarity of 310 mOsm/L for faster absorption
• C Added potassium-free formulation to prevent hyperkalaemia
• D Lower sodium concentration of 75 mmol/L and total osmolarity of 245 mOsm/L ✓

Explanation

The reduced-osmolarity WHO ORS contains sodium 75 mmol/L, chloride 65 mmol/L, potassium 20 mmol/L, citrate 10 mmol/L, glucose 75 mmol/L, giving a total osmolarity of 245 mOsm/L compared with 311 in the older formula. Lower osmolarity reduces stool volume, vomiting and the need for unscheduled intravenous fluids. Glucose was lowered to 75 mmol/L, and potassium is retained because hypokalaemia complicates cholera.

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.