What is the recommended dose of vasopressin (antidiuretic hormone) for various medical conditions?

Vasopressin Dosing Recommendations for Various Medical Conditions

For septic shock, the recommended dose of vasopressin is 0.01-0.07 units/minute, with most guidelines specifically recommending 0.03 units/minute as the optimal dose when added to norepinephrine. 1, 2, 3

Septic Shock

• Vasopressin is recommended as a second-line vasopressor after norepinephrine in septic shock 1, 2
• The standard dose is 0.03 units/minute when added to norepinephrine 1, 2, 3
• Dose range for septic shock: 0.01-0.07 units/minute 4
• Vasopressin should not be used as the single initial vasopressor for septic shock 1
• Doses higher than 0.03-0.04 units/minute should be reserved for salvage therapy (when other vasopressors have failed to achieve target MAP) 1, 3

Post-Cardiotomy Shock

• Recommended dose range: 0.03-0.1 units/minute 4
• Can be added to norepinephrine to either raise mean arterial pressure or decrease norepinephrine dosage 1, 3

Vasodilatory Shock (Non-Septic)

• Vasopressin is indicated for adults with vasodilatory shock who remain hypotensive despite fluids and catecholamines 4
• Particularly useful in vasoplegic shock without reduced left ventricular systolic function 5
• Dosing similar to septic shock: 0.03 units/minute as standard dose 3

Administration Considerations

• Vasopressin requires dilution before administration:
  • Dilute 20 units/mL with normal saline (0.9% sodium chloride) or 5% dextrose to either 0.1 units/mL or 1 unit/mL 4
  • Discard unused diluted solution after 18 hours at room temperature or 24 hours under refrigeration 4
• Central venous access is required for administration 2
• Continuous arterial blood pressure monitoring is essential 2, 3

When to Initiate Vasopressin

• Most clinicians initiate vasopressin when norepinephrine dose reaches 0.25-0.50 μg/kg/min 5
• Typical timing is after 2-6 hours of norepinephrine administration if target MAP is not achieved 5
• Should be added after initial fluid resuscitation and first-line vasopressor therapy 2, 5

When to Discontinue Vasopressin

• Tapering should begin when mean arterial pressure target is achieved and maintained 5
• Most clinicians recommend progressive discontinuation rather than abrupt cessation 5
• Typically discontinued after the first-line vasopressor (norepinephrine) has been reduced below a predefined threshold 5

Cautions and Contraindications

• Can worsen cardiac function 4
• May cause reversible diabetes insipidus 4
• Common adverse reactions include decreased cardiac output, bradycardia, tachyarrhythmias, hyponatremia, and ischemia (coronary, mesenteric, skin, digital) 4
• Contraindicated in patients with known allergy or hypersensitivity to vasopressin or chlorobutanol 4
• Use with caution in patients at risk for mesenteric or digital ischemia 5

Pharmacokinetics

• Onset of action: Peak effect within 15 minutes 4
• Duration: Pressor effect fades within 20 minutes after stopping infusion 4
• Half-life: ≤10 minutes at doses used for vasodilatory shock 4
• Clearance: 9-25 mL/min/kg in patients with vasodilatory shock 4

Vasopressin's mechanism of action involves binding to V1 receptors on vascular smooth muscle, causing vasoconstriction in most vascular beds including splanchnic, renal, and cutaneous circulation 4, 6.