Veterinary drug · Drug monograph

Hypertonic Saline (7.2–7.5% NaCl): veterinary dose and monograph

Hypertonic Saline (7.2–7.5% NaCl) is a veterinary drug. A concentrated saline solution used for SMALL-VOLUME RESUSCITATION and OSMOTHERAPY. Indications include small-volume resuscitation of hypovolaemic/haemorrhagic shock (esp. large animals/field, GDV); osmotherapy for raised intracranial pressure / cerebral oedema (head trauma); rapid transient plasma-volume expansion when large isotonic volumes are impractical. This monograph lists 6 reference doses for dogs, cats, cattle and horses, each with route, frequency and source, plus meat and milk withdrawal periods for food animals.

At a glance

Drug class: Veterinary drug
Also known as: HTS, Hypertonic sodium chloride, 7.5% saline
Species with doses: Dogs, Cats, Cattle and Horses
Routes: IV
Last reviewed: 1 October 2026

Indications

Small-volume resuscitation of hypovolaemic/haemorrhagic shock (esp. large animals/field, GDV)
Osmotherapy for raised intracranial pressure / cerebral oedema (head trauma)
Rapid transient plasma-volume expansion when large isotonic volumes are impractical

Hypertonic Saline (7.2–7.5% NaCl) dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

Hypertonic Saline (7.2–7.5% NaCl) doses for dogs
Indication	Dose	Route	Frequency	Duration
Small-volume shock resuscitation	7.2% NaCl 3–8 mL/kg IV at ≤1 mL/kg/min (haemorrhagic shock 4–5 mL/kg over 10 min)	IV	single slow bolus, then isotonic fluids	—
Neurologic trauma / raised intracranial pressure	7–7.5% NaCl 3–5 mL/kg IV over 15–20 minutes, then crystalloids	IV	single infusion, then crystalloids	—

Small-volume shock resuscitation: Plumb’s 10e p.634 (dogs/cats, extra-label): low-volume resuscitation with 7–7.5% alone — 4–6 mL/kg IV at no more than 1 mL/kg/minute (2–8 mL/kg has been noted), followed by crystalloids; with a colloid — 23.4% NaCl mixed 1:2 with 6% hetastarch, 4–5 mL/kg IV over 5 minutes. Papich 5e (Sodium Chloride 7.2%/7.5%): 3–8 mL/kg IV, not faster than 1 mL/kg/min; 4 mL/kg over 5 min in septic shock. Effect is transient — follow with isotonic crystalloid ± colloid. Do not give to hypernatraemic or dehydrated patients.
Neurologic trauma / raised intracranial pressure: Plumb’s 10e p.634 (dogs/cats, extra-label): neurologic trauma using hypertonic saline alone — recommendations vary, but 3–5 mL/kg IV over 15 to 20 minutes has been noted; follow with crystalloids. Do NOT use in hyponatraemic patients; monitor sodium. Plumb’s mannitol monograph notes hypertonic saline may be preferable to mannitol in hypovolaemic patients.

Cats

Hypertonic Saline (7.2–7.5% NaCl) doses for cats
Indication	Dose	Route	Frequency	Duration
Shock resuscitation (small-volume)	7.2% NaCl 3–8 mL/kg IV at ≤1 mL/kg/min (low end in cats), then isotonic fluids	IV	once, slow	—

Shock resuscitation (small-volume): Papich 5e (dogs and cats): 3–8 mL/kg IV, not faster than 1 mL/kg/min. Plumb’s 10e p.634 (dogs/cats): 4–6 mL/kg IV at ≤1 mL/kg/minute, and some clinicians suggest cats receive the LOW end of the range; follow with crystalloids. Not for dehydration or hypernatraemia.

Cattle

Hypertonic Saline (7.2–7.5% NaCl) doses for cattle
Indication	Dose	Route	Frequency	Duration	Withdrawal
Shock / rapid resuscitation	7.2% NaCl 4–8 mL/kg IV at 1 mL/kg/min, followed by oral or IV isotonic fluids	IV	once, then isotonic	—	no slaughter withdrawal
Neonatal calf diarrhoea (adjunct)	7.2% NaCl 5 mL/kg IV over 3–10 minutes, with oral isotonic electrolyte solution	IV	once, with oral electrolytes	—	no slaughter withdrawal

Shock / rapid resuscitation: Papich 5e (large animals): 4–8 mL/kg of 7.2% at 1 mL/kg/min; no withdrawal time suggested.
Neonatal calf diarrhoea (adjunct): Plumb’s 10e p.634 (extra-label): 7.2% hypertonic saline 5 mL/kg IV over 3 to 10 minutes along with 60 mL of an isotonic electrolyte solution PO (repeated twice, at 8 and 16 hours), as printed.

Horses

Hypertonic Saline (7.2–7.5% NaCl) doses for horses
Indication	Dose	Route	Frequency	Duration
Shock resuscitation	7.2% NaCl 4–8 mL/kg IV at 1 mL/kg/min, then large-volume isotonic fluids	IV	single bolus	—

Shock resuscitation: Papich 5e (large animals): 4–8 mL/kg of 7.2% IV at 1 mL/kg/min. Plumb’s 10e p.634 (extra-label) cites only an endurance-ride study: an initial IV bolus of 2 litres per horse (NOT L/kg) of 7.2% plus 5 litres per horse of lactated Ringer’s (with 250 mL 23% calcium gluconate), then more LRS as needed. Not for dehydrated or hypernatraemic horses.

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

Hypertonic Saline (7.2–7.5% NaCl) doses for buffalo
Indication	Dose	Route	Frequency	Duration	Withdrawal
Shock / rapid resuscitation	7.2% NaCl 4–8 mL/kg IV at 1 mL/kg/min, followed by oral or IV isotonic fluids	IV	once, then isotonic	—	no slaughter withdrawal
Neonatal calf diarrhoea (adjunct)	7.2% NaCl 5 mL/kg IV over 3–10 minutes, with oral isotonic electrolyte solution	IV	once, with oral electrolytes	—	no slaughter withdrawal

Shock / rapid resuscitation: Papich 5e (large animals): 4–8 mL/kg of 7.2% at 1 mL/kg/min; no withdrawal time suggested.
Neonatal calf diarrhoea (adjunct): Plumb’s 10e p.634 (extra-label): 7.2% hypertonic saline 5 mL/kg IV over 3 to 10 minutes along with 60 mL of an isotonic electrolyte solution PO (repeated twice, at 8 and 16 hours), as printed.

Contraindications

Dehydration / free-water deficit and hypernatraemia (worsens them). Uncontrolled haemorrhage without haemostasis (may increase bleeding via improved pressure/dilution). Cardiac failure/fluid-overload states. Rapid IV bolus (bradycardia, hypotension, bronchospasm). Severe hyperosmolar states. Known hypersensitivity.

Adverse effects

Hypernatraemia / hyperchloraemia and hyperosmolality (transient)
Bradycardia, hypotension, bronchospasm with rapid infusion
Phlebitis/haemolysis (concentrated); rebound hypovolaemia (transient effect)
Worsening of dehydration if free-water deficit present

Drug interactions

Subsequent isotonic crystalloids/colloids: needed to sustain the transient volume effect
Concurrent free-water-deficit states/hypertonic agents: additive hypernatraemia/hyperosmolality
No specific drug incompatibilities beyond usual saline considerations

Pregnancy and lactation

Used for resuscitation when clinically necessary; monitor sodium/fluid status.

Monitoring

Serum sodium and osmolality (before and after) — avoid over-shooting/rapid swings
Blood pressure/perfusion and the need for follow-on isotonic fluids (transient effect)
Neurological status (osmotherapy); heart rate/respiration during infusion
Hydration status (avoid in free-water-deficit patients)

Toxicity and overdose

Overdose/over-rapid infusion causes hypernatraemia, hyperosmolality, hyperchloraemic acidosis, bradycardia/hypotension/bronchospasm, and can worsen a pre-existing free-water deficit (dangerous in dehydrated/hypernatraemic patients). Too-rapid correction of chronic hyponatraemia risks osmotic demyelination. Extravasation/high concentration can cause phlebitis/haemolysis.

Management: Stop the infusion; assess sodium/osmolality and correct carefully (avoid rapid sodium swings). Support with appropriate isotonic/hypotonic fluids and monitor neurologically. Manage bradycardia/bronchospasm from rapid infusion supportively. Continuous monitoring of electrolytes and volume status.

Clinical pearls

Small volume, big effect — a few mL/kg rapidly expands blood volume in shock (great for large animals/GDV/field) and pulls water out of a swollen brain (osmotherapy for raised ICP)
The effect is TRANSIENT (~30 min) — ALWAYS follow with isotonic crystalloid ± colloid
Give SLOWLY (rapid bolus → bradycardia/hypotension/bronchospasm) and NEVER to a dehydrated or hypernatraemic patient
Monitor sodium/osmolality and avoid rapid sodium swings (osmotic demyelination risk with chronic hyponatraemia)

Mechanism of action

The high sodium concentration creates a steep osmotic gradient that rapidly draws water from the interstitial and intracellular compartments into the intravascular space, transiently expanding plasma volume and improving cardiac output/perfusion with a small infused volume. It also has microcirculatory and mild positive-inotropic/vasoregulatory effects. In the brain (with an intact blood–brain barrier) the same osmotic pull removes water from cerebral tissue, reducing intracranial pressure. Because the sodium redistributes within ~30 minutes, the volume effect is short-lived unless followed by maintenance fluids.

Formulations and products

Injection 7.2 / 7.5 % NaCl (dilute/prepare per protocol)
3 % NaCl (osmotherapy)
Hypertonic Saline 3 % / 7.5 % — 3 % / 7.5 % NaCl, IV infusion (human-label)

Storage

Injection: 15–30 °C, do not freeze; prepare/dilute per protocol. Inspect for crystallisation (warm/redissolve if needed).

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Frequently asked questions

What is the dose of Hypertonic Saline (7.2–7.5% NaCl) for dogs?

Reference doses for Hypertonic Saline (7.2–7.5% NaCl) in dogs: 7.2% NaCl 3–8 mL/kg IV at ≤1 mL/kg/min (haemorrhagic shock 4–5 mL/kg over 10 min) IV single slow bolus, then isotonic fluids (Small-volume shock resuscitation); 7–7.5% NaCl 3–5 mL/kg IV over 15–20 minutes, then crystalloids IV single infusion, then crystalloids (Neurologic trauma / raised intracranial pressure). Confirm against the label and the patient before use.

What is the dose of Hypertonic Saline (7.2–7.5% NaCl) for cats?

Reference doses for Hypertonic Saline (7.2–7.5% NaCl) in cats: 7.2% NaCl 3–8 mL/kg IV at ≤1 mL/kg/min (low end in cats), then isotonic fluids IV once, slow (Shock resuscitation (small-volume)). Confirm against the label and the patient before use.

What is the dose of Hypertonic Saline (7.2–7.5% NaCl) for cattle?

Reference doses for Hypertonic Saline (7.2–7.5% NaCl) in cattle: 7.2% NaCl 4–8 mL/kg IV at 1 mL/kg/min, followed by oral or IV isotonic fluids IV once, then isotonic (Shock / rapid resuscitation); 7.2% NaCl 5 mL/kg IV over 3–10 minutes, with oral isotonic electrolyte solution IV once, with oral electrolytes (Neonatal calf diarrhoea (adjunct)). Confirm against the label and the patient before use.

What is the withdrawal period for Hypertonic Saline (7.2–7.5% NaCl)?

Cattle, IV (Shock / rapid resuscitation): no slaughter withdrawal; Cattle, IV (Neonatal calf diarrhoea (adjunct)): no slaughter withdrawal. Follow the product label and national regulations where they differ.

When should Hypertonic Saline (7.2–7.5% NaCl) not be used?

What are the side effects of Hypertonic Saline (7.2–7.5% NaCl) in animals?

Hypernatraemia / hyperchloraemia and hyperosmolality (transient); Bradycardia, hypotension, bronchospasm with rapid infusion; Phlebitis/haemolysis (concentrated); rebound hypovolaemia (transient effect); Worsening of dehydration if free-water deficit present.

Sources

Plumb's Veterinary Drug Handbook
Merck Veterinary Manual, 11th edition
Papich, Papich Handbook of Veterinary Drugs, 5th edition

Last reviewed 1 October 2026 · VetMasterJi