ORS mainly contains?

ESIC Nursing Officer 2016 (Shift -2)

Pharmacology

Easy

Appeared in: ESIC Nursing Officer 2016 (Shift -2)

Explanation

Oral Rehydration Solution (ORS) primarily works through the coupled transport of sodium and glucose in the small intestine.
The Sodium-Glucose Cotransporter 1 (SGLT1) on the intestinal wall requires both sodium and glucose to be present to actively transport them into the body.
This active transport creates an osmotic gradient, which causes water to be passively absorbed from the intestines into the bloodstream, thus combating dehydration.

Option B: Calcium carbonate is an antacid or calcium supplement; it is not a component of the standard WHO ORS formula.
Option C: While older ORS formulas contained sodium bicarbonate to correct acidosis, it has been replaced by trisodium citrate dihydrate in the current WHO formula because citrate is more stable and has a longer shelf life.
Option D: ORS contains potassium to replace losses from diarrhea, but it is in the form of potassium chloride (KCl), not potassium bicarbonate.

Visual 1: Diagram: The Sodium-Glucose Cotransport (SGLT1) mechanism in an intestinal epithelial cell, showing how sodium, glucose, and water are absorbed.
Visual 2: Infographic: Composition of WHO low-osmolarity ORS, visually breaking down the grams of each component per liter of water.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Composition and mechanism of Oral Rehydration Solution (ORS) as background academic context rather than a clinical decision trigger.
Administering ORS is a critical first-line intervention for managing mild to moderate dehydration, especially in children with diarrhea, significantly reducing mortality.
Nurses must educate caregivers on the correct preparation (one packet in 1 liter of clean, safe water) and storage (discard after 24 hours) to ensure efficacy and prevent contamination.
What if? If a patient is severely dehydrated with signs of shock (e.g., lethargy, very weak pulse, inability to drink), ORS is insufficient. The priority action changes to initiating intravenous (IV) fluid resuscitation immediately.

How to Approach the Question

First, identify the core subject of the question: the main components of Oral Rehydration Solution (ORS).
This is a factual recall question. Access your knowledge about the physiological basis of ORS therapy.
Recall that the primary purpose of ORS is to rehydrate the body by promoting water absorption in the gut.
The key mechanism for this is the sodium-glucose co-transport system. This means both sodium and glucose are essential for its primary function.
Evaluate the options based on this core mechanism. 'Sodium and glucose' directly matches this physiological principle.
Eliminate other options by recalling that while other electrolytes like potassium are present, they are not the primary drivers of water absorption, and other listed compounds (calcium carbonate, potassium bicarbonate) are not standard components.

Concept Tested & Keywords

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