Vasopressin Drip Dosing and Management
Add vasopressin at a fixed dose of 0.03 units/minute as a second-line agent when norepinephrine alone fails to maintain a MAP ≥65 mmHg in septic shock—never use it as monotherapy or as a first-line vasopressor. 1, 2
Indications for Vasopressin Initiation
- Start vasopressin when norepinephrine requirements remain elevated despite adequate fluid resuscitation (minimum 30 mL/kg crystalloid) and target MAP of 65 mmHg cannot be achieved 1, 2
- Vasopressin is FDA-approved for vasodilatory shock (septic shock and post-cardiotomy shock) in adults who remain hypotensive despite fluids and catecholamines 3
- Never initiate vasopressin as the sole initial vasopressor—it must be added to norepinephrine, not used as first-line monotherapy 1, 2
Dosing Protocol
Septic Shock
- Standard fixed dose: 0.03 units/minute when added to norepinephrine 1, 2
- FDA-approved dose range: 0.01-0.07 units/minute 1, 3
- Do not titrate vasopressin like other vasopressors—use as a fixed-dose infusion at 0.03 units/minute 1
- Doses higher than 0.03-0.04 units/minute should be reserved only for salvage therapy when all other vasopressors have failed 1
Post-Cardiotomy Shock
- FDA-approved dose range: 0.03-0.1 units/minute 3
- Add to norepinephrine to either raise MAP or decrease norepinephrine requirements 1
Preparation and Administration
- Dilute the 20 units/mL vial with normal saline or D5W to either 0.1 units/mL or 1 unit/mL 3
- Discard unused diluted solution after 18 hours at room temperature or 24 hours under refrigeration 3
- Requires central venous access for administration 1, 2
Hemodynamic Goals and Monitoring
- Target MAP ≥65 mmHg with continuous arterial blood pressure monitoring via arterial catheter 1, 2
- Once vasopressin is added, you can either raise MAP to target OR decrease norepinephrine dosage while maintaining hemodynamic stability 1
- Monitor cardiac output when using vasopressin, as it is a pure vasopressor without cardiac stimulation effects 2
- Recent evidence shows no difference in hemodynamic response between 0.03 units/min and 0.04 units/min dosing 4
Escalation Strategy for Refractory Shock
- If MAP remains <65 mmHg despite norepinephrine plus vasopressin 0.03 units/minute, add epinephrine (0.05-2 mcg/kg/min) as the third-line agent rather than increasing vasopressin dose 1, 2
- For persistent hypoperfusion despite adequate vasopressor support, add dobutamine (up to 20 mcg/kg/min) rather than escalating vasopressors further 1, 2
- Do not increase vasopressin beyond 0.03-0.04 units/minute for routine management—higher doses are associated with increased adverse effects including cardiac arrest 1, 5
Critical Monitoring Requirements
- Establish arterial catheter placement as soon as practical for all patients requiring vasopressors 1, 2
- Monitor for signs of inadequate perfusion beyond MAP: rising lactate, decreased urine output, worsening mental status, or digital ischemia 1, 6
- Watch for adverse effects including decreased cardiac output, bradycardia, tachyarrhythmias, hyponatremia, and ischemia (coronary, mesenteric, skin, digital) 3
- Vasopressin can cause gastrointestinal hypoperfusion and ischemic skin lesions 7
Common Pitfalls and Contraindications
- Never use vasopressin as monotherapy—it must always be combined with norepinephrine 1, 2
- Contraindicated in patients with known allergy to 8-L-arginine vasopressin or chlorobutanol 3
- Can worsen cardiac function and may induce uterine contractions in pregnancy 3
- Doses >0.04 units/min were associated with cardiac arrests in early case series, with all but one arrest occurring at ≥0.05 units/min 5
- Avoid titrating vasopressin like traditional vasopressors—use as a fixed-dose adjunct 1
- In hypodynamic sepsis models, vasopressin can compromise oxygen delivery and decrease systemic and gut blood flow 7