What is the shock dose of vasopressin?

Shock Dose of Vasopressin

The shock dose of vasopressin is 0.01-0.03 units/minute for septic shock, with a starting dose of 0.01 units/minute that can be titrated up by 0.005 units/minute every 10-15 minutes until target blood pressure is reached. 1

Dosing Guidelines for Vasopressin in Shock States

FDA-Approved Dosing

• Starting dose: 1
  • Septic shock: 0.01 units/minute
  • Post-cardiotomy shock: 0.03 units/minute
• Titration: Increase by 0.005 units/minute every 10-15 minutes until target blood pressure is achieved
• Maximum dose: Limited data exists for doses above 0.07 units/minute for septic shock and 0.1 units/minute for post-cardiotomy shock 1
• Weaning: After target blood pressure has been maintained for 8 hours without catecholamines, taper by 0.005 units/minute every hour as tolerated 1

Administration Considerations

• Vasopressin should be diluted in normal saline (0.9% sodium chloride) or 5% dextrose in water (D5W) prior to intravenous administration 1
• Discard unused diluted solution after 18 hours at room temperature or 24 hours under refrigeration 1
• Ideally administered through a central venous catheter to reduce risk of extravasation and tissue necrosis 2

Clinical Context and Indications

Role in Septic Shock

• Vasopressin is typically used as a second-line agent after norepinephrine in septic shock 3
• It may be particularly effective in patients with vasodilatory septic shock and catecholamine hyporesponsiveness 3
• The VASST trial demonstrated no difference in 28-day mortality between norepinephrine alone versus norepinephrine plus vasopressin at 0.03 units/minute in the overall population 3, 4
• However, a subgroup analysis showed improved survival with vasopressin in patients receiving lower doses of norepinephrine (< 15 μg/min) 3

Physiologic Effects and Benefits

• Vasopressin's action is independent of catecholamine receptor stimulation, making it effective even with alpha-adrenergic receptor down-regulation in septic shock 3
• It increases mean arterial pressure (MAP), systemic vascular resistance (SVR), and urine output in vasodilatory shock 3
• Recent evidence suggests vasopressin may reduce the need for renal replacement therapy compared to norepinephrine 5

Target Blood Pressure

• The target mean arterial pressure (MAP) is generally 65 mmHg in most patients 2
• Higher blood pressure targets may be needed for patients with traumatic brain injury, spinal injuries, elderly patients, or those with chronic hypertension 2

Monitoring and Safety Considerations

Required Monitoring

• Continuous arterial blood pressure monitoring is recommended 2
• Assess tissue perfusion markers, including:
  • Lactate levels
  • Skin perfusion
  • Mental status
  • Urine output
  • Mixed or central venous oxygen saturations 2
• Daily electrolytes, urea nitrogen, and creatinine should be monitored during active titration 2

Potential Adverse Effects

• Higher doses of vasopressin (>0.04 units/minute) have been associated with cardiac, digital, and splanchnic ischemia 3
• Excessive vasoconstriction may compromise microcirculatory flow 3, 2
• Risk of extravasation increases with peripheral administration, particularly with infusion duration >24 hours 2

Important Caveats

• Vasopressin is not currently recommended for treatment of cardiogenic shock and should not be used without ScvO2/CO monitoring in this context 3
• Ensure adequate fluid resuscitation before or concurrent with vasopressin initiation 2
• Cardiac output measurement targeting maintenance of normal or elevated flow is desirable when using pure vasopressors like vasopressin 3

By following these evidence-based dosing guidelines and monitoring parameters, vasopressin can be effectively and safely used in the management of shock states, particularly in patients with vasodilatory shock who are refractory to or require high doses of catecholamines.