Drug | Functional class (predominant receptor or mechanism of action) | Bolus dose | Infusion dose | Comments |
Ephedrine | Inotrope/chronotrope/vasopressor (alpha1-adrenergic receptor agonist; beta1- and beta2-adrenergic receptor agonist) | 5 to 10 mg boluses | N/A | - Tachyphylaxis may occur with multiple repeated doses due to indirect postsynaptic release of norepinephrine
- Cardiovascular effects attenuated by drugs that block ephedrine uptake into adrenergic nerves (eg, cocaine) or those that deplete norepinephrine reserves (eg, reserpine)
- Administered with extreme caution (eg, in small incremental doses of 2.5 mg) to patients using monoamine oxidase (MAO) inhibitors or methamphetamines since exaggerated hypertensive responses or life-threatening dysrhythmias may occur
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Phenylephrine | Vasopressor (alpha1-adrenergic receptor agonist) | 50 to 100 mcg boluses (may begin infusion if repeated bolus doses are necessary) | 10 to 100 mcg/minute or 0.1 to 1 mcg/kg/minute | - Often selected to treat hypotension if normal or elevated HR is present
- Genetic polymorphisms lead to variable individual responses
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Norepinephrine | Inotrope/vasopressor (alpha1- and beta1-adrenergic receptor agonist) | 4 to 8 mcg (may begin infusion if repeated bolus doses are necessary) | 1 to 20 mcg/minute or 0.01 to 0.3 mcg/kg/minute | - Often selected as a first-line agent during noncardiac surgery, particularly for treatment of most types of shock
- Norepinephrine 8 mcg is approximately equivalent in potency to phenylephrine 100 mcg
- Peripheral extravasation of a high concentration may cause tissue damage
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Epinephrine | Inotrope/chronotrope/vasopressor (alpha1-adrenergic receptor agonist; beta1- and beta2-adrenergic receptor agonist) | 4 to 10 mcg initially; up to 100 mcg boluses may be used when initial response is inadequate | 1 to 100 mcg/minute or 0.01 to 1 mcg/kg/minute Note changing effects across dose range: - Low doses have primarily beta2-adrenergic effects at 1 to 2 mcg/minute or 0.01 to 0.02 mcg/kg/minute
- Intermediate doses have primarily beta1- and beta2-adrenergic effects at 2 to 10 mcg/minute or 0.02 to 0.1 mcg/kg/minute
- High doses have primarily alpha1-adrenergic effects at 10 to 100 mcg/minute or 0.1 to 1 mcg/kg/minute
| - First-line treatment for cardiac arrest and for anaphylaxis
- May be administered IV, IM, or via an endotracheal tube in emergencies
- Low doses cause bronchodilatory effects and may cause arterial vasodilation and decreased BP
- Intermediate doses cause increases in HR and BP
- High doses cause vasoconstriction, with possible severe hypertension and adverse metabolic effects
- Individual responses to dose-related effect are variable
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Vasopressin | Vasopressor (vasopressin1 and vasopressin2 receptor agonist) | 1 to 4 units | 0.01 to 0.04 units/minute Doses >0.04 units/minute up to 0.1 units/minute are reserved for salvage therapy (ie, failure to achieve adequate BP goals with other vasopressor agents)¶ | - Effective for treatment of hypotension refractory to administration of catecholamines or sympathomimetics such as ephedrine, phenylephrine, or norepinephrine
- No direct effect on HR
- Little effect on PVR; can cause splanchnic vasoconstriction
- Individual responses to dose-related effects are variable
- Peripheral extravasation may cause skin necrosis
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Dopamine | Inotrope/vasopressor/dose-dependent chronotropy (dopaminergic, beta1-, beta2-, and alpha1-adrenergic receptor agonist) | N/A | 2 to 20 mcg/kg/minute Note changing effects across dose range: - Low doses have primarily dopaminergic effects at <3 mcg/kg/minute
- Intermediate doses have primarily beta1- and beta2-adrenergic effects at 3 to 10 mcg/kg/minute
- High doses have primarily alpha1-adrenergic effects >10 mcg/kg/minute
| - Low doses may exacerbate hypotension via beta2 stimulation
- High doses may cause vasoconstriction, adverse metabolic effects, and arrhythmias
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Dobutamine | Inotrope/vasodilator/dose-dependent chronotropy (beta1- and beta2-adrenergic receptor agonist) | N/A | 1 to 20 mcg/kg/minute | - Exacerbation of hypotension is possible due to dose-dependent vasodilation (via beta2 stimulation); concurrent administration of a potent vasoconstrictor such as norepinephrine or vasopressin may be necessary
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Milrinone | Inotrope/vasodilator (phosphodiesterase inhibitor) (decreases rate of cyclic adenosine monophosphate [cAMP] degradation) | N/A | 0.375 to 0.75 mcg/kg/minute (a loading dose of 50 mcg/kg over ≥10 minutes may be administered, but may be omitted to avoid hypotension) | - Exacerbation of hypotension is likely due to vasodilation (via phosphodiesterase inhibition); concurrent administration of a potent vasoconstrictor such as norepinephrine or vasopressin may be necessary
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Isoproterenol | Inotrope/chronotrope/vasodilator (beta1- and beta2-adrenergic receptor agonist) | N/A | 5 to 20 mcg/minute or 0.05 to 0.2 mcg/kg/minute | - Exacerbation of hypotension is likely due to dose-dependent vasodilation (via beta2 stimulation)
- May cause arrhythmias
- Not available in most settings
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