What are the recommended initial dosages of vasopressors, such as norepinephrine, epinephrine, and vasopressin, for critically ill patients with hypotension?

From the Guidelines

For critically ill patients with hypotension, the recommended initial vasopressor dosages are: norepinephrine starting at 0.01-0.05 mcg/kg/min, titrated up to 0.5-1 mcg/kg/min as needed; epinephrine starting at 0.01-0.05 mcg/kg/min, titrated up to 0.5 mcg/kg/min; and vasopressin typically dosed at a fixed rate of 0.01-0.04 units/min (commonly 0.04 units/min) 1. Norepinephrine is generally the first-line agent due to its predominant alpha-adrenergic effects that increase systemic vascular resistance with minimal chronotropic effects. These medications should be administered through a central venous catheter whenever possible to prevent tissue damage from extravasation. Target mean arterial pressure (MAP) is typically 65 mmHg or higher, though individualization based on patient characteristics is important. Some key points to consider when using vasopressors include:

• The use of norepinephrine as the first-choice vasopressor (strong recommendation, moderate quality of evidence) 1
• The addition of either vasopressin (up to 0.03 U/min) or epinephrine to norepinephrine with the intent of raising MAP to target, or adding vasopressin to decrease norepinephrine dosage (weak recommendation, moderate quality of evidence) 1
• The use of dopamine as an alternative vasopressor agent to norepinephrine only in highly selected patients (weak recommendation, low quality of evidence) 1
• The recommendation against using low-dose dopamine for renal protection (strong recommendation, high quality of evidence) 1 Continuous hemodynamic monitoring is essential during administration, including blood pressure, heart rate, urine output, and mental status. Vasopressors address hypotension by increasing vascular tone and cardiac contractility, but they don't treat the underlying cause of shock, which must be identified and addressed simultaneously for optimal outcomes. It is also suggested that all patients requiring vasopressors have an arterial catheter placed as soon as practical if resources are available (weak recommendation, very low quality of evidence) 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Initial dose of 0.25 mL to 0. 375 mL (from 8 mcg to 12 mcg of base) per minute, adjust the rate of flow to establish and maintain a low to normal blood pressure (usually 80 mm Hg to 100 mm Hg systolic) sufficient to maintain the circulation of vital organs. Post-cardiotomy shock: 0.03 to 0.1 units/minute Septic shock: 0.01 to 0. 07 units/minute

The recommended initial dosages of vasopressors are:

• Norepinephrine: 8-12 mcg per minute, with an average maintenance dose of 2-4 mcg per minute 2
• Vasopressin:
  • Post-cardiotomy shock: 0.03-0.1 units/minute
  • Septic shock: 0.01-0.07 units/minute 3 Note: The information for epinephrine is not available in the provided drug labels.

From the Research

Vasopressor Dosages

The recommended initial dosages of vasopressors, such as norepinephrine, epinephrine, and vasopressin, for critically ill patients with hypotension are as follows:

• Norepinephrine: The initial dose is typically started at 0.05-0.1 μg/kg/min and titrated to achieve an adequate arterial pressure 4, 5.
• Epinephrine: The initial dose is typically started at 0.05-0.1 μg/kg/min and titrated to achieve an adequate arterial pressure 4, 6.
• Vasopressin: The initial dose is typically started at 0.01-0.04 units/min and titrated to achieve an adequate arterial pressure 4, 7.

Key Considerations

When choosing the initial dosage of vasopressors, the following factors should be considered:

• The patient's condition, including the severity of hypotension and the presence of organ dysfunction 5, 8.
• The patient's response to initial fluid resuscitation and the need for additional hemodynamic support 4, 8.
• The potential risks and benefits of each vasopressor, including the risk of adverse events such as excessive vasoconstriction and organ ischemia 6, 8.

Titration and Monitoring

The dosage of vasopressors should be titrated to achieve an adequate arterial pressure, while monitoring the patient's hemodynamic response and adjusting the dosage as needed 4, 8. The use of vasopressors should be guided by the patient's individual needs and response to treatment, rather than a one-size-fits-all approach 5, 7.