What is the recommended oral rehydration solution (ORS) for treating dehydration?

Oral Rehydration Solution Recommendations

For oral rehydration, use low-osmolarity oral rehydration solutions (ORS) containing 75-90 mEq/L sodium for active rehydration and 40-60 mEq/L sodium for maintenance, with commercially available products like Pedialyte (45 mEq/L) or CeraLyte being appropriate options—never use apple juice, Gatorade, or soft drinks. 1

Sodium Concentration Based on Clinical Context

The choice of ORS depends on whether you are actively rehydrating a dehydrated patient versus maintaining hydration:

For Active Rehydration (Correcting Existing Dehydration)

• Solutions containing 75-90 mEq/L sodium are preferred for rehydrating patients with mild to moderate dehydration 1
• This higher sodium concentration is particularly important when purging rates exceed 10 mL/kg/hour 1
• The Infectious Diseases Society of America strongly recommends ORS for all infants, children, and adults with mild to moderate dehydration until clinical dehydration is corrected 1

For Maintenance Therapy (Preventing Dehydration)

• Solutions containing 40-60 mEq/L sodium are recommended once rehydration is complete 1
• These lower sodium concentrations better match the stool sodium losses seen in typical viral diarrhea 1
• When using higher sodium solutions (>60 mEq/L) for maintenance, supplement with low-sodium fluids like breast milk, formula, or water to prevent sodium overload 1

Commercially Available Products

Appropriate ORS Products

The most widely used commercial solutions in the United States include:

• Pedialyte (45 mEq/L sodium) 1
• Ricelyte (50 mEq/L sodium) 1
• CeraLyte 1
• Enfalac Lytren 1

While these products contain lower sodium concentrations than the ideal 75-90 mEq/L for rehydration, they can be used effectively when the alternative would be intravenous fluids or physiologically inappropriate beverages 1

Beverages to Avoid

Never use the following for rehydration: 1

• Apple juice
• Gatorade or sports drinks
• Commercial soft drinks
• These contain inappropriate electrolyte concentrations and excessive osmolality that can worsen diarrhea 1

Administration Strategy

For Mild to Moderate Dehydration

• Administer ORS orally until clinical signs of dehydration resolve 1
• Replace ongoing losses: 60-120 mL for children <10 kg and 120-240 mL for children >10 kg per diarrheal stool or vomiting episode 1
• For adults, allow ad libitum intake up to approximately 2 L/day 1

Special Technique for Vomiting Patients

• Give small volumes (5-10 mL) every 1-2 minutes using a spoon or syringe 2
• Gradually increase volume as tolerated 2
• Never allow a thirsty child to drink large volumes at once from a cup or bottle, as this worsens vomiting 2
• Over 90% of vomiting children can be successfully rehydrated using this approach 2

For Severe Dehydration

• Begin with intravenous isotonic fluids (lactated Ringer's or normal saline) until pulse, perfusion, and mental status normalize 1
• Transition to ORS once the patient is stable and can tolerate oral intake 1
• IV therapy is also indicated for shock, altered mental status, ileus, or failure of ORS therapy 1

Composition and Formulation Details

WHO Low-Osmolarity ORS

The World Health Organization recommends low-osmolarity ORS (total osmolarity <250 mmol/L) as first-line therapy for dehydration from all causes 1

Key Components

• Modern ORS formulations use citrate instead of bicarbonate for longer shelf life, with equivalent efficacy 1
• The coupled sodium-glucose transport mechanism remains intact during diarrhea, enabling water absorption 1
• A well-balanced ORS should contain 65-70 mEq/L sodium and 75-90 mmol/L glucose for optimal absorption 1

Critical Pitfalls to Avoid

• Do not allow rapid, large-volume drinking in vomiting patients—this exacerbates symptoms 2
• Do not use sports drinks or juice for rehydration—these lack appropriate electrolyte composition 1
• Do not withhold food during or after rehydration—early feeding reduces severity and duration of diarrhea 1, 2
• Do not dilute formula after rehydration—full-strength formula is appropriate and dilution provides no benefit 2
• Monitor for hypernatremia when using higher sodium solutions, particularly in elderly patients or those with chronic heart or kidney disease 1

When to Escalate Care

Consider intravenous therapy when: 1

• Severe dehydration with shock is present
• Altered mental status exists
• ORS therapy fails (approximately 4% of cases)
• Paralytic ileus is present
• Patient cannot tolerate oral intake despite nasogastric administration