B. 5-Catecholamines Flashcards
list the direct-acting sympathomimetic (catecholamines)
and their receptor agonist
Epinephrine β₁ β₂ β₃> 𝝰₁ 𝝰₂ Norepinephrine 𝝰₁ 𝝰₂> β₁ Dopamine D₁ > β₁ > 𝝰₁ Isoprenaline β₁ =β₂ Dobutamine β₁ >β₂>>> (𝝰₁), selective β₁ (higher affinity, less positive chronotropic than dopamin)
pharmacological characteristics of catecholamines
parenteral administration
short duration of action
NO CNS entry
what is the dose-dependent effect of Epinephrine?
Low dose: β₁ β₂ predominates–> HR, SV, CO, Pulse pressure ↑, vasodilation TPR, BP ↓, bronchodilation
High dose: 𝝰₁ stimulation predominates –> vasoconstriction (TPR, BP ↑, reflex bradycardia)
main indications for Epinephrine (5)
cardiac arrest, complete heart block Anaphylactic shock hypotensive emergency adjunct to local anesthetics (reduce local blood flow) acute asthma attack
SE of epinephrine
hypertension arrhythmia stroke MI Pulmonary edema
main indications for Norepinephrine (4)
cardiac arrest, complete heart block
hypotensive emergency
adjunct to local anesthetics (reduce local blood flow)
shock (cardiogenic, neurogenic, septic)
SE of norepinephrine
vasospasm tissue necrosis hypertension arrhythmia MI
what are the dose-dependent effects of dopamine?
Low dose: D₁ stimulation (renal perfusion ↑)
medium-dose: β₁ stimulation (cardiac stimulation)
high dose: 𝝰₁, acts like epinephrine (loses selectivity)
when do we give dopamine?
SHOCK (especially with renal failure)
SE of dopamine
arrhythmia
indications for isoprenaline
cardiac arrest, complete heart block (IV)
acute asthma attack (nebulizer)
indications for dobutamine
cardiogenic shock
acute heart failure
Cardiac stress test
