What is a common result of using vasopressors such as norepinephrine or phenylephrine?

Using vasopressors like norepinephrine or phenylephrine leads to increased blood pressure primarily through their mechanism of action. These medications work by stimulating alpha-adrenergic receptors, which causes vasoconstriction of the blood vessels. As the blood vessels constrict, peripheral resistance increases, thereby elevating systemic vascular resistance. This rise in resistance contributes to an increase in blood pressure.

While vasopressors may support improved perfusion pressure in critically ill patients, their predominant effect is indeed the direct increase in blood pressure. This is essential in conditions like septic shock, where maintaining adequate perfusion and blood flow is critical for organ function.

In contrast, vasopressors do not typically increase cardiac output significantly, as they may even provoke reflex bradycardia and potentially worsen myocardial oxygen demand. Additionally, vasopressors can lead to decreased urine output due to renal vasoconstriction and reduced renal perfusion, which can occur as a consequence of the systemic effects of these medications.