see also:

• inotropes
• alpha adrenergic agonists
• sympathomimetics

• vasopressors increase vascular tone, resulting in raised mean arterial pressure (MAP), and systemic vascular resistance.
• inotropes are drugs that increase the force and velocity of myocardial contraction resulting in increased contractility and stroke volume, and therefore cardiac output.
• inotropes and vasopressors are used in the Mx of shock such as sepsis / septicaemia
• most agents have varying effects depending upon their dose given the variation in their activity on the various receptors
• effects may also occur due to reflex actions, eg. reflex bradycardia with lowered cardiac output may occur with agents that cause hypertension.
• excessive vasoconstriction due to use of vasopressors results in inadequate tissue perfusion of the extremities, mesenteric organs and kidneys.

• metaraminol (Aramine)
  • often used at induction of anaesthesia to counteract the hypotensive effects of induction agents
• argipressin (vasopressin / ADH)
  • may have a role in refractory cases of anaphylaxis, sepsis / septicaemia
• adrenaline / epinephrine
  • alpha 1, beta 1 and some beta 2 activity - high doses cause vasoconstriction to prevail over beta 2 agonist skeletal muscle vasodilatation. Inotrope, chronotrope activity.
  • most often used in anaphylaxis, choking / respiratory arrest / cardiac arrest / BLS / ALS / CPR
• noradrenaline / norepinephrine
  • alpha 1 and beta 1 activity mainly so vasoconstriction with some inotropy but the reflex bradycardia often cancels out any chronotropy
  • 1st line for sepsis / septicaemia not responding to iv fluid Rx
• phenylephrine
  • pure alpha adrenergic agonist activity thus vasoconstriction with little inotropy or chronotropy