Vasopressin
Arginine vasopressin / Antidiuretic hormone (ADH)
Also known as: Pitressin · Neo-Lidocaton · Pressyn · ADH · Antidiuretic hormone · 8-arginine vasopressin · beta-hypophamine
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Diagnostic agent (Exogenous vasopressin test after water deprivation test) | 2.5 mU/kg IV over one hour | IV | Once | 1 hour | 🌎 NA |
| Adjunctive treatment of vasodilatory shock (unresponsive to fluids/catecholamines) | 0.01-0.04 Units/minute IV | IV | CRI | — | 🌎 NA |
| CPCR (pulseless electrical activity or ventricular asystole) | 0.2-0.8 Units/kg, IV once | IV | Once | — | 🌎 NA |
- Diagnostic agent (Exogenous vasopressin test after water deprivation test): Give aqueous vasopressin in D5W. Empty bladder and collect urine at 30, 60, and 90 minutes.
- Adjunctive treatment of vasodilatory shock (unresponsive to fluids/catecholamines): Dose is not dependent upon patient weight. DO NOT exceed 0.04 Units/minute (risk of myocardial ischemia). DO NOT use in cardiogenic shock.
- CPCR (pulseless electrical activity or ventricular asystole): May be beneficial for myocardial and cerebral blood flow.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Diagnostic agent (after water deprivation test) | 0.5 U/kg IM | IM | Once | — | 🌎 NA |
| Adjunctive treatment of vasodilatory shock (unresponsive to fluids/catecholamines) | 0.01-0.04 Units/minute IV | IV | CRI | — | 🌎 NA |
| CPCR (pulseless electrical activity or ventricular asystole) | 0.2-0.8 Units/kg, IV once | IV | Once | — | 🌎 NA |
- Diagnostic agent (after water deprivation test): Empty bladder and determine specific gravity at 30, 60, and 120 minutes after administration.
- CPCR (pulseless electrical activity or ventricular asystole): May be beneficial for myocardial and cerebral blood flow.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Vasopressin, also known as antidiuretic hormone (ADH), is an endogenous peptide hormone synthesized in the hypothalamus and stored in the posterior pituitary gland. In veterinary medicine, it serves several critical roles:
- Diagnostic Agent: Used primarily in the water deprivation test to differentiate between central and nephrogenic diabetes insipidus.
- Emergency & Critical Care: Increasingly utilized as an adjunctive treatment for vasodilatory shock and during cardiopulmonary cerebral resuscitation (CPCR).
Clinical Pearl: In states of severe shock or cardiac arrest (ventricular asystole/pulseless electrical activity), vasopressin offers distinct advantages over epinephrine. It induces profound vasoconstriction even in acidotic environments, spares coronary and renal vasculature (improving myocardial perfusion), and lacks the arrhythmogenic and chronotropic effects associated with catecholamines.
Historically used to treat central diabetes insipidus, it has largely been replaced by the synthetic analog desmopressin (DDAVP) for long-term management due to the discontinuation of long-acting oil-based formulations.
Mechanism of action
Vasopressin exerts its effects via multiple receptor subtypes:
- V1 Receptors (Vascular Smooth Muscle): Mediates profound vasoconstriction. At high doses, it causes contraction of capillaries and small arterioles, increasing systemic vascular resistance and blood pressure. It also stimulates smooth muscle in the bladder, gallbladder, and GI tract.
- V2 Receptors (Renal Collecting Ducts): Mediates antidiuretic effects. Vasopressin binds to V2 receptors → activates adenylate cyclase → increases cAMP → promotes the insertion of aquaporin-2 channels into the luminal membrane → increases water permeability and reabsorption of solute-free water → concentrates urine and decreases urine flow.
- V3 Receptors (Pituitary): Stimulates the release of corticotropin (ACTH).
- Oxytocin & Purinergic (P2) Receptors: Minimal oxytocic effects at standard doses, but massive doses can stimulate uterine contraction.
Safety & warnings
Contraindications
- Known hypersensitivity to vasopressin
- Chronic nephritis until nitrogen retention is resolved to reasonable levels
- Cardiogenic shock (due to risk of myocardial ischemia)
Adverse effects
- Local irritation at the injection site
- Sterile abscesses
- Skin reactions
- Platelet aggregation
- Bilirubinemia
- Abdominal pain
- Hematuria
- Hypersensitivity (urticarial) reactions
- Water intoxication (with overdosage)
Precautions
Important Warnings
- Cardiovascular Disease: Use with extreme caution in patients with vascular disease or heart failure due to potent vasoconstrictive properties. High doses can cause myocardial ischemia.
- Other Conditions: Use cautiously in patients with seizure disorders or asthma.
- Pregnancy: FDA Category C. Has minimal effects on uterine contractions at usual doses, but should be used with caution in pregnant animals as animal studies have shown adverse fetal effects.
- Diagnostic Use: The water deprivation test (WDT) is contraindicated in animals that are already dehydrated or have known renal disease.
Drug interactions
May inhibit the antidiuretic activity of vasopressin
May inhibit the antidiuretic activity of vasopressin
May inhibit the antidiuretic activity of vasopressin
May inhibit the antidiuretic activity of vasopressin
May inhibit the antidiuretic activity of vasopressin
May potentiate the antidiuretic effects of vasopressin
May potentiate the antidiuretic effects of vasopressin
May potentiate the antidiuretic effects of vasopressin
May potentiate the antidiuretic effects of vasopressin
May potentiate the antidiuretic effects of vasopressin
May potentiate the antidiuretic effects of vasopressin
May potentiate the antidiuretic effects of vasopressin
Monitoring
- Urine output and frequency
- Water consumption
- Urine specific gravity
- Urine osmolality
- Blood pressure and ECG (when used for shock/CPCR)
Pharmacokinetics
Absorption
Destroyed in the GI tract prior to absorption; must be administered intranasally or parenterally. After IM or SC administration in dogs, aqueous vasopressin has antidiuretic activity for 2-8 hours.
Distribution
Distributed throughout the extracellular fluid. Apparently not bound to plasma proteins.
Metabolism
Rapidly destroyed in the liver and kidneys.
Elimination
Cleared rapidly by hepatic and renal degradation. In humans, the plasma half-life is reported to be only 10-20 minutes.
Overdose
Water Intoxication
Overdosage of vasopressin leads to excessive water retention and subsequent water intoxication (dilutional hyponatremia).
- Early Signs: Listlessness, depression, and lethargy.
- Severe Signs: Coma, seizures, and eventually death due to cerebral edema.
Treatment:
- Mild Intoxication: Discontinue vasopressin therapy and strictly restrict water access until clinical signs resolve.
- Severe Intoxication: May require the administration of osmotic diuretics (e.g., mannitol, urea, or dextrose) with or without a loop diuretic like furosemide to rapidly excrete excess free water.
Available products
Formulations
- Injection: 20 pressor Units/mL
Human-labeled
- Vasopressin Injection: 20 pressor Units/mL in 0.5 mL, 1 mL & 10 mL vials (Pitressin Synthetic, generic)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store aqueous injection at room temperature; avoid freezing. For intravenous or intra-arterial infusion, it may be diluted in either 5% Dextrose in Water (D5W) or normal saline.
Client information
Information for Pet Owners
- Hospital Use Only: Vasopressin is an injectable medication primarily used by veterinarians in a hospital setting. It is used either to diagnose specific types of excessive drinking/urination disorders (like Diabetes Insipidus) or as a life-saving emergency drug during severe shock or cardiac arrest.
- Diagnostic Testing: If your pet is undergoing a "water deprivation test," they will be closely monitored in the hospital. Vasopressin is given at the end of the test to see if your pet's kidneys can concentrate urine in response to the hormone.
- Long-term Treatment: While vasopressin was historically used to treat Diabetes Insipidus at home, it has largely been replaced by a safer, more convenient synthetic drop or tablet called desmopressin (DDAVP).
- Safety: Because it strongly constricts blood vessels, your veterinary team will monitor your pet's heart and blood pressure closely if it is used in an emergency.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.