Inotropes and Vasopressors 3

Inotropes and Vasopressors

A Guide by Medicinoz App

Dosage Calculator

Select Drug Dopamine Dobutamine Norepinephrine Phenylephrine Epinephrine Milrinone

Usual range: 2-20 mcg/kg/min

Patient Weight (kg)

Desired Dosage (mcg/kg/min)

Drug Concentration (mcg/mL)

Required to calculate flow rate (mL/hr).

Infusion Rate

0.0 mL/hr

Beta-Adrenergic Agonists

Dobutamine

• Predominantly β1 agonist, some β2 activity
• Used in cardiogenic shock with adequate BP
• Dosage: 2.5-20 mcg/kg/min IV
• Can be mixed with noradrenaline

Dopamine

• Low dose: renal vasodilation
• Moderate dose: β1 agonist
• High dose: α1 agonist
• Must be diluted in D5W

Phosphodiesterase-3 Inhibitors

Milrinone

• Loading dose: 50 mcg/kg over 10 mins
• Great for RV failure
• Watch for hypotension

Alpha-Adrenergic Agonists

Norepinephrine (Noradrenaline)

• Strong vasoconstriction (α1) with some contractility (β1)
• First line for septic shock
• Avoid peripheral administration (necrosis risk)

Phenylephrine

• Pure α1 agonist
• Can cause reflex bradycardia
• Useful in tachyarrhythmias requiring pressors

Quick Reference Table

Agent	Mechanism	Indications	Key Notes
Dobutamine	β1 agonist	Cardiogenic shock, Low CO	Causes tachycardia
Dopamine	Dose-dependent	Bradycardia, Hypotension	Arrhythmogenic
Norepinephrine	α1 > β1	Septic shock (1st line)	Central line preferred
Epinephrine	α + β agonist	Cardiac arrest, Anaphylaxis	↑ Lactate, ischemia risk
Milrinone	PDE3 Inhibitor	Acute HF, RV failure	Renally cleared