Prescribing Guides
ORS (Oral Rehydration Salts) Prescribing Guide for Indian Clinical Practice
ORS prescribing guide for Indian clinicians covering WHO/UNICEF formulation, dehydration assessment, zinc supplementation and NEET PG high-yield points.
MedNext Editorial Team | 2026-08-01 | 8 min read
ORS (Oral Rehydration Salts) Prescribing Guide for Indian Clinical Practice
ORS prescribing guide for Indian clinicians covering WHO/UNICEF formulation, dehydration assessment, zinc supplementation and NEET PG high-yield points.
Oral Rehydration Salts (ORS) is the single most important intervention in diarrhoeal disease management and one of the greatest public health innovations of the 20th century. ORS prevents and treats dehydration due to acute diarrhoea of any aetiology, saving millions of lives annually, particularly in India.
Clinical Pharmacology Overview
ORS works on the principle of glucose-sodium co-transport. In the small intestinal epithelium, the SGLT1 (sodium-glucose linked transporter 1) co-transporter actively absorbs one molecule of glucose with one molecule of sodium, driving water absorption osmotically. This mechanism remains intact even during secretory diarrhoea (e.g., cholera), where the secretory and absorptive pathways are independent.
The reduced osmolarity ORS (245 mOsm/L) adopted by WHO in 2003 is more effective than the original formula (311 mOsm/L), reducing stool output, vomiting, and the need for IV supplementation.
Composition per litre (WHO/UNICEF reduced osmolarity ORS): - Sodium chloride: 2.6 g (Na+ 75 mEq/L, Cl- 65 mEq/L) - Potassium chloride: 1.5 g (K+ 20 mEq/L) - Trisodium citrate dihydrate: 2.9 g (citrate 10 mmol/L) - Anhydrous glucose: 13.5 g (glucose 75 mmol/L) - Total osmolarity: 245 mOsm/L
Indian Brand Names and Government Supply
- Electral (FDC Limited) -- most widely recognised ORS brand in India
- WHO-ORS (Government of India supply through ASHA workers and public health centres)
- Enerzal ORS (multiple manufacturers)
- Walyte (Wallace)
- Numerous generic ORS sachets available at Jan Aushadhi centres
Approved Indications in Indian Clinical Practice
- Acute diarrhoea of any cause (viral, bacterial, parasitic) -- prevention and treatment of dehydration
- Cholera
- Gastroenteritis in children and adults
- Post-operative oral rehydration
- Exercise-induced dehydration (though sports drinks differ in composition)
- Heat-related dehydration
Dosing and Administration
Preparation: dissolve one sachet (20.5 g) in 1 litre of clean drinking water. Use within 24 hours if kept at room temperature (or 48 hours if refrigerated). Do not boil the prepared solution (degrades glucose).
WHO Plan A (no dehydration): - After each loose stool: 50-100 mL for children under 2 years, 100-200 mL for children 2-10 years, as much as desired for older children and adults. - Continue breastfeeding and normal feeding.
WHO Plan B (some dehydration): - 75 mL/kg over 4 hours. - Reassess after 4 hours and reclassify.
WHO Plan C (severe dehydration): - Start IV fluids (Ringer lactate preferred) immediately. - Give ORS (5 mL/kg/hour) as soon as patient can drink, alongside IV therapy. - Transition to oral rehydration as tolerated.
Zinc supplementation: always co-prescribe zinc with ORS for children with diarrhoea. Zinc 20 mg/day (above 6 months) or 10 mg/day (under 6 months) for 10-14 days.
Important Considerations
- ORS does NOT stop diarrhoea -- it prevents and treats dehydration
- Do not add sugar or salt to the prepared solution (alters osmolarity)
- Do not dilute with less or more than 1 litre of water
- Vomiting is NOT a contraindication -- give small frequent sips (5 mL every 1-2 minutes)
- ORS can be given via nasogastric tube if the child refuses to drink
- Anti-diarrhoeal drugs (loperamide) are NOT recommended in children with acute diarrhoea
- Antibiotics are needed only for specific indications (bloody diarrhoea/dysentery, cholera, proven bacterial cause)
Side Effects and Monitoring
Side effects are rare and related to improper preparation: - Hypernatraemia: if prepared with too little water - Hyponatraemia: if prepared with too much water - Vomiting: may occur initially but usually resolves with small, frequent sips
Monitoring: hydration status (skin turgor, mucous membranes, capillary refill, urine output, fontanelle in infants). Weight if baseline available. Reassess after each 4-hour ORT period.
Special Populations
Pregnancy: Completely safe. Essential for managing hyperemesis gravidarum-related dehydration and acute gastroenteritis in pregnancy.
Renal impairment: Use with caution in severe renal impairment or anuric patients (potassium content). Monitor electrolytes.
Neonates: Can be used in neonates, but breastfeeding remains the first priority. Refer early for neonatal diarrhoea.
Malnourished children: Use ReSoMal (Rehydration Solution for Malnutrition) instead of standard ORS in severe acute malnutrition -- standard ORS has too much sodium and too little potassium for malnourished children.
NEET PG High-Yield Points
- SGLT1 co-transporter: glucose-sodium co-transport is the mechanism of ORS
- Reduced osmolarity ORS (245 mOsm/L) is the current WHO standard
- Glucose-to-sodium ratio must be 1:1 (equimolar) for optimal absorption
- ORS does NOT reduce stool output -- it replaces fluid losses
- Zinc supplementation reduces diarrhoea duration and future episodes for 2-3 months
- ReSoMal for severely malnourished children (NOT standard ORS)
- WHO Plan A, B, C classification for dehydration management
- Rice-based ORS may reduce stool output in cholera (not standard in NLEM but tested)
- ORT (oral rehydration therapy) has been called the most important medical advance of the 20th century
- Lancet called it "potentially the most important medical advance of this century" (1978)
Indian Regulatory Status
ORS is classified as an essential medicine by the Government of India and is included in the NLEM. It is available over the counter without prescription. ORS sachets are distributed free through the public health system (PHCs, sub-centres, ASHA workers) and are available at subsidised rates through Jan Aushadhi centres. The Indian Pharmacopoeia specifies the exact composition. ORS is one of the cornerstone interventions in India's Integrated Management of Neonatal and Childhood Illness (IMNCI) programme.
Frequently Asked Questions
What is the composition of reduced osmolarity ORS?
The WHO/UNICEF reduced osmolarity ORS contains sodium chloride 2.6 g, potassium chloride 1.5 g, trisodium citrate dihydrate 2.9 g, and anhydrous glucose 13.5 g per litre. Total osmolarity is 245 mOsm/L (reduced from the old formula of 311 mOsm/L). India adopted the reduced osmolarity formulation.
Why does ORS contain glucose?
Glucose is essential for ORS because sodium absorption in the small intestine is coupled to glucose absorption via the SGLT1 (sodium-glucose linked transporter 1) co-transporter. Without glucose, sodium (and therefore water) absorption is dramatically reduced. This glucose-sodium co-transport mechanism is the scientific basis for ORT and is why ORS works even during active secretory diarrhoea.
Should zinc be given with ORS?
Yes. WHO and IAP (Indian Academy of Pediatrics) recommend zinc supplementation along with ORS for all children with diarrhoea. Zinc 20 mg/day for children over 6 months (10 mg/day for under 6 months) for 10-14 days reduces diarrhoea duration, severity, and recurrence for the next 2-3 months.
Can ORS be used in cholera?
Yes. ORS is the first-line treatment for cholera dehydration. In severe cholera, IV Ringer lactate is given initially for rapid rehydration, then ORS is continued for maintenance. Even in severe cases, ORS reduces the IV fluid requirement. ORS saves lives in cholera epidemics where IV access is limited.
How much ORS should be given?
WHO Plan B (some dehydration): 75 mL/kg over 4 hours. WHO Plan A (no dehydration): after each loose stool, give 50-100 mL (under 2 years), 100-200 mL (2-10 years), or as much as desired (above 10 years and adults). Reassess hydration status frequently.
Continue reading
Prescribing GuidesMetformin Prescribing Guide for Indian Clinical Practice
Evidence-based metformin prescribing for Indian clinicians covering dosing, brands, interactions, monitoring and NEET PG high-yield points.
Prescribing GuidesCeftriaxone Prescribing Guide for Indian Clinical Practice
Complete ceftriaxone prescribing reference for Indian clinicians covering indications, dosing, reconstitution, drug interactions and NEET PG points.
Prescribing GuidesAmoxicillin Prescribing Guide for Indian Clinical Practice
Comprehensive amoxicillin prescribing reference for Indian doctors covering dosing, brands, resistance patterns and NEET PG high-yield pharmacology.
Continue with Prescribing Guides
Apply what you have read with clinical prescribing MCQs that test real decision-making: drug choice, dose selection, interactions and monitoring.
Try prescribing questionsBrowse all prescribing guides