Ringer’s Solution

Plain Ringer’s solution is an isotonic crystalloid containing sodium, potassium, calcium and chloride. It is used primarily for replacement of extracellular fluid and electrolyte losses. Its composition differs from lactated or acetate-buffered Ringer’s solutions because it does not contain a metabolizable buffer, which affects its acid–base profile.

Group

Electrolyte replacement fluid

Mechanism of Action

Ringer’s solution supplies extracellular electrolytes and water, expanding circulating and interstitial fluid compartments. Sodium and accompanying anions support extracellular osmotic balance, while potassium and calcium provide smaller electrolyte contributions. Redistribution limits the proportion remaining intravascular over time. Its chloride-rich, unbuffered composition influences the acid–base effect of larger-volume administration.

Dose Rates

Dogs

Use / stage	Dose	Route	Instructions
Maintenance fluids	Reference only	IV	55-65 mL/kg/day IV, SC or IP. The reported guidance also approximates this as 2.5 mL/kg/hour.
Maintenance fluids	Reference only	SC	55-65 mL/kg/day SC; balance absorption and hydration needs.
Maintenance fluids	Reference only	IP	55-65 mL/kg/day IP, as reported.
Dehydration replacement	Reference only	IV	Moderate dehydration: 15-30 mL/kg/hour IV; severe: 50 mL/kg/hour IV, with reassessment and overload monitoring.

Cats

Use / stage	Dose	Route	Instructions
Maintenance fluids	Reference only	IV	55-65 mL/kg/day IV, SC or IP. The reported guidance also approximates this as 2.5 mL/kg/hour.
Maintenance fluids	Reference only	SC	55-65 mL/kg/day SC; balance absorption and hydration needs.
Maintenance fluids	Reference only	IP	55-65 mL/kg/day IP, as reported.
Dehydration replacement	Reference only	IV	Moderate dehydration: 15-30 mL/kg/hour IV; severe: 50 mL/kg/hour IV, with reassessment and overload monitoring.

Large_animals

Use / stage	Dose	Route	Schedule	Instructions
Maintenance fluids	Reference only	IV		40-50 mL/kg/day IV, SC or IP; moderate dehydration 15-30 mL/kg/hour IV and severe 50 mL/kg/hour IV.

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Calf dehydration	Reference only	IV		Moderate: total 45 mL/kg at 30-40 mL/kg/hour IV. Severe: total 80-90 mL/kg at 30-40 mL/kg/hour, up to 80 mL/kg/hour if necessary. Reassess continuously.

Indications

Replacement of dehydration-associated extracellular fluid and electrolyte deficits in veterinary patients.
Crystalloid volume support in selected hypovolemic patients.
Perioperative replacement of extracellular fluid losses.
Selected ongoing fluid support where its electrolyte composition is appropriate to the patient’s requirements.

Contraindications

Fluid overload risk; reported maximum rate 80 mL/kg/hour is not a routine target.

Interactions

Calcium can be incompatible with other medicines; do not add bicarbonate directly to a calcium-containing fluid.

Adverse effects

Fluid overload and chloride-associated acidification.

Monitoring and Administration

Monitor hydration, pulmonary signs and electrolytes. Distinguish plain Ringer solution from lactated or acetate formulations. Replacement deficit in liters is body weight multiplied by fractional dehydration (e.g. 0.08 for 8%).

Plain Ringer reported electrolyte composition per liter: sodium 147 mEq, potassium 4 mEq, chloride 155 mEq and calcium 4 mEq. Salt masses are not provided.