Version July 2025
| Vasopressor | Mechanism of action | Typical prophylactic infusion dose | Typical therapeutic bolus dose | Advantages | Disadvantages |
| Phenylephrine | Direct alpha-1 | 25 to 75 mcg/minute | 50 to 100 mcg IV | Increases blood pressure Prophylactic infusions reduce hypotension and intraoperative nausea and vomiting | May result in compensatory bradycardia |
| Ephedrine | Indirect sympathomimetic alpha-1, beta-1 and beta-2-adrenergic receptors | N/A | 5 to 10 mg IV | Increases heart rate and blood pressure | Slightly lower umbilical artery pH compared with phenylephrine |
| Norepinephrine* | Direct acting sympathomimetic alpha-1, alpha-2 beta-1 and beta-2-adrenergic receptors | 2.5 to 4 mcg per minute | 4 to 8 mcg IV | Increases blood pressure and maintains heart rate Prophylactic infusions reduce hypotension and intraoperative nausea and vomiting | Increased risk of tissue necrosis if infusion extravasates |
IV: intravenous.
* Optimal doses of norepinephrine for prevention and treatment of spinal hypotension have not been established. The doses shown are reasonable doses that have been used in studies.
