From the Guidelines
The optimal dose of vasopressin for septic shock is 0.03 units/minute as a continuous intravenous infusion, as recommended by the most recent guidelines 1.
Key Considerations
- Vasopressin is generally used as an adjunct to norepinephrine rather than as a first-line vasopressor.
- When initiating vasopressin, it should be added to an existing norepinephrine infusion when moderate doses have been reached.
- The fixed-dose approach is preferred over titrating vasopressin based on blood pressure response.
- Vasopressin works by binding to V1 receptors on vascular smooth muscle, causing vasoconstriction, particularly in the splanchnic circulation.
- The addition of vasopressin often allows for reduction in norepinephrine doses, potentially decreasing catecholamine-associated adverse effects.
Clinical Application
- Vasopressin should be continued until the patient is hemodynamically stable and vasopressor support can be weaned.
- It is essential to monitor the patient's response to vasopressin and adjust the dose accordingly.
- The use of vasopressin in septic shock is supported by guidelines from the Surviving Sepsis Campaign 1.
Mechanism of Action
- Vasopressin stimulates a family of receptors—V1a (vasoconstriction), V1b (ACTH release), V2 (anti-diuretic effects), oxytocin (vasodilator) and purinergic receptors (of limited relevance to septic shock) 1.
- Vasopressin paradoxically induces synthesis of nitric oxide (NO), which may limit vasopressin’s vasoconstriction, while preserving renal perfusion 1.
From the FDA Drug Label
The recommended starting dose is: ... Septic Shock: 0. 01 units/minute Titrate up by 0.005 units/minute at 10-to 15-minute intervals until the target blood pressure is reached. There are limited data for doses above 0.1 units/minute for post-cardiotomy shock and 0. 07 units/minute for septic shock.
The optimal dose of vasopressin for septic shock is 0.01 units/minute as a starting dose, with titration up to 0.07 units/minute as needed and tolerated, to maintain target blood pressure 2.
- Key considerations:
- Titrate to the lowest dose compatible with a clinically acceptable response
- Adverse reactions are expected to increase with higher doses
- Taper vasopressin injection by 0.005 units/minute every hour as tolerated to maintain target blood pressure after it has been maintained for 8 hours without the use of catecholamines 2.
From the Research
Optimal Dose of Vasopressin for Septic Shock
- The optimal dose of vasopressin for septic shock is not explicitly stated in the provided studies, but the studies suggest that vasopressin can be used as an adjuvant therapy to norepinephrine in septic shock patients who are refractory to norepinephrine alone 3, 4.
- A study by 5 used a vasopressin loading dose of 1 U, followed by a continuous infusion of 1 U/h, and found that this approach may be safe and effective in predicting responses to vasopressin infusion.
- Another study by 6 used a push-dose of 1 unit of intravenous vasopressin to improve hemodynamics in a patient with vasodilatory septic shock, and found that it was effective in improving blood pressure.
- The dose of vasopressin used in these studies varied, but the typical dose range for vasopressin in septic shock is 0.01-0.04 U/min 4.
Comparison with Norepinephrine
- A systematic review and meta-analysis by 7 found that there were no significant differences in 28-day mortality rates, ICU mortality, length of ICU stay, length of hospital stay, mean arterial pressure at 24 h, urine output at 24 h, and serious adverse events between patients treated with vasopressin versus norepinephrine as the first-line vasopressor in septic shock.
- However, the study found that patients treated with vasopressin had lower chances of requiring renal replacement therapy (RRT) compared to those treated with norepinephrine 7.
Safety and Efficacy
- The studies suggest that vasopressin can be a safe and effective adjuvant therapy to norepinephrine in septic shock patients who are refractory to norepinephrine alone 3, 4, 5.
- However, the use of vasopressin should be carefully considered and monitored, as it can cause adverse effects such as digital ischemia, mesenteric ischemia, and myocardial ischemia 5.