What is the recommended dosage of vasopressin (antidiuretic hormone) for treating septic shock?

Vasopressin Dosage for Septic Shock

The recommended dosage of vasopressin for treating septic shock is 0.01-0.03 units/minute, with a starting dose of 0.01 units/minute that can be titrated up by 0.005 units/minute at 10-15 minute intervals until target blood pressure is reached, with doses above 0.07 units/minute not recommended due to limited data on safety. 1, 2

Initial Vasopressor Selection and Sequencing

• Norepinephrine is the first-choice vasopressor for septic shock with a target mean arterial pressure (MAP) of 65 mmHg 3, 2
• Vasopressin should not be used as the single initial vasopressor for septic shock but rather as a second-line agent added to norepinephrine 3, 2
• Vasopressin is indicated when target MAP cannot be achieved with norepinephrine alone or to decrease norepinephrine dosage 3, 2

Vasopressin Dosing Protocol

• Starting dose: 0.01 units/minute 1, 2
• Titration: Increase by 0.005 units/minute at 10-15 minute intervals until target blood pressure is reached 1
• Maximum recommended dose: 0.03-0.04 units/minute for standard therapy 3, 2
• Doses above 0.07 units/minute have limited safety data and are not recommended 1, 2
• Doses higher than 0.03-0.04 units/minute should be reserved for salvage therapy (when other vasopressors have failed to achieve target MAP) 3, 2

Administration Requirements

• Vasopressin must be diluted in normal saline (0.9% sodium chloride) or 5% dextrose in water (D5W) prior to intravenous administration 1
• Central venous access is required for administration 2
• Arterial catheter placement is recommended for continuous blood pressure monitoring 3, 2
• Discard unused diluted solution after 18 hours at room temperature or 24 hours under refrigeration 1

Weaning Protocol

• After target blood pressure has been maintained for 8 hours without catecholamines, taper vasopressin by 0.005 units/minute every hour as tolerated 1
• Evidence suggests that vasopressin should be discontinued last (after norepinephrine) in resolving septic shock to reduce the risk of rebound hypotension 4

Clinical Considerations

• Vasopressin deficiency may occur in up to one-third of patients with septic shock, contributing to refractory hypotension 5
• The primary benefit of vasopressin is its norepinephrine-sparing effect, which may reduce complications associated with high-dose catecholamines 4, 5
• Vasopressin at low doses may cause vasodilation in coronary, cerebral, and pulmonary arterial circulations 6
• Adverse effects are expected to increase with higher doses, particularly those above 0.04 units/minute 1, 6

Monitoring

• Monitor MAP continuously via arterial line 3, 2
• Watch for potential adverse effects including cardiac ischemia, digital ischemia, and splanchnic hypoperfusion 6
• Monitor for thrombocytopenia, which has been reported with vasopressin analogues 7
• Assess for signs of improved tissue perfusion (e.g., improved lactate clearance, urine output) 2

Common Pitfalls

• Using vasopressin as a first-line agent instead of norepinephrine 3, 2
• Exceeding the recommended dose range (>0.03-0.04 units/minute) outside of salvage therapy 3, 2
• Failing to ensure adequate volume resuscitation before initiating vasopressors 2
• Discontinuing vasopressin before other vasopressors, which may lead to rebound hypotension 4
• Not using an arterial line for continuous blood pressure monitoring in patients receiving vasopressors 3, 2