What is the recommended dose of vasopressin (antidiuretic hormone)?

Vasopressin Dosing Recommendations

For acute variceal hemorrhage in cirrhosis, vasopressin should be administered as a continuous IV infusion at 0.2-0.4 units/minute, which can be increased to a maximum of 0.8 units/minute, and must always be accompanied by IV nitroglycerin starting at 40 mcg/minute (up to 400 mcg/minute) to maintain systolic blood pressure ≥90 mmHg, with a maximum duration of 24 hours. 1

Context-Specific Dosing

Variceal Hemorrhage (Most Common Indication for Vasopressin)

• Starting dose: 0.2-0.4 units/minute as continuous IV infusion 1
• Maximum dose: 0.8 units/minute 1
• Mandatory co-administration: IV nitroglycerin at 40 mcg/minute initially, titrated up to 400 mcg/minute to maintain systolic BP ≥90 mmHg 1
• Duration: Maximum 24 hours to minimize serious cardiovascular and ischemic side effects 1
• Important caveat: Octreotide is the only vasoactive drug available in the United States for this indication and is preferred over vasopressin due to superior safety profile 1, 2

Septic Shock and Vasodilatory Shock

• Starting dose: 0.01 units/minute (per FDA label) 3
• Titration: Increase by 0.005 units/minute every 10-15 minutes until target blood pressure achieved 3
• Maximum dose: 0.07 units/minute for septic shock; limited data exists for doses above this threshold 3, 2
• Post-cardiotomy shock: Starting dose 0.03 units/minute, maximum 0.1 units/minute 3
• Critical principle: Vasopressin should never be used as the sole vasopressor agent; it is a second-line agent added to norepinephrine 2, 4
• Optimal range: Most evidence supports 0.01-0.04 units/minute as the safest and most effective range 5, 4, 6

Administration Guidelines

Preparation and Route

• Dilution required: Dilute 20 units/mL vasopressin in normal saline or D5W prior to IV administration 3
• Stability: Discard unused diluted solution after 18 hours at room temperature or 24 hours refrigerated 3
• Access: Central venous access is strongly preferred to minimize extravasation risk 7

Monitoring Requirements

• Blood pressure and heart rate: Every 5-15 minutes during initial titration 7
• Target: Mean arterial pressure of 65 mmHg in septic shock 7, 2
• Urine output: Monitor for improvement (target >50 mL/hour for at least 4 hours) 1

Tapering Protocol

• After target blood pressure maintained for 8 hours without catecholamines, taper by 0.005 units/minute every hour as tolerated 3
• When norepinephrine decreases to 0.2 mcg/kg/minute, withdraw vasopressin in small steps according to MAP response 8

Critical Safety Considerations

Serious Adverse Effects

• Cardiovascular: Cardiac and peripheral ischemia, arrhythmias, hypertension, bowel ischemia 1, 5
• Dose-dependent toxicity: Doses >0.04 units/minute associated with increased adverse effects including cardiac arrest 6
• Gastrointestinal: Hypoperfusion and ischemic complications 4
• Dermal: Ischemic skin lesions 4

Contraindications and Precautions

• Volume status: Address hypovolemia with fluid resuscitation BEFORE initiating vasopressin 7, 4
• Duration limits: For variceal bleeding, use only for 24 hours maximum due to cumulative ischemic risk 1
• Combination therapy: Always use with norepinephrine in shock states; never as monotherapy 2, 4

Clinical Pearls

The key distinction is indication: Variceal hemorrhage requires higher doses (0.2-0.8 units/minute) for only 24 hours with mandatory nitroglycerin co-administration, while septic shock requires much lower doses (0.01-0.04 units/minute) as an adjunct to norepinephrine 1, 3, 4. The evidence strongly favors octreotide over vasopressin for variceal bleeding when available due to superior safety profile and ability to use for 2-5 days 1, 2.