Direct-acting adrenoceptor agonists - catecholamines Flashcards
Direct-acting adrenoceptor agonists - groups
Catecholamines
Noncatecholamines
Catecholamines - 5 drugs + affinity for receptors
Norepinephrine (α1= α2, β1 > β2) Epinephrine (α1= α2, β1 = β2) Dopamine (D1> β1 > α) Isoproterenol (β1 = β2>> α) Dobutamine (β1 > β2 > α)
Vasopressors - what are they?
Catecholamines that increase blood pressure
Catecholamines - MOA
Bind to and activate adrenoceptors, increasing the sympathetic stimulation of e.g vascular and cardiac tissue
Catecholamines - adverse effects
Tissue necrosis.
Decreased organ perfusion.
Excessive cardiac stimulation.
Hyperglycemia (β-agonitst)
Catecholamines - contraindications
Be careful with β-agonitst in pts with diabetes
Norepinephrine - indications
Hypotension (after high dose of vasodilators).
Septic and cardiogenic shock.
Norepinephrine - adverse effects
Reflex bradycardia
Epinephrine - indications
Anaphylactic shock. Cardiac arrest. Ventricular fibrillation. Surgery: Bleeding. Prolong action of local anesthetic
Epinephrine - effects on BP
Low doses: Lower diastolic BP (β2).
High doses: Higher diastolic and systolic BP (α1)
Dopamine - indications
Cardiogenic, septic and hypovolemic shock.
Heart failure.
Cardiovascular effect of dopamine according to dosing
Low doses: Renal vasodilation (D1).
Medium doses: cardiac stimulation (β1).
High doses: increased BT+ vasoconstriction (β1+α1)
How can dopamine act as an indirect adrenoceptor agonits?
It stimulates norepinephrine release.
Isoproterenol - indications
AV-block, bradycardia
Cardiovascular effect of isoproterenol
Vasodilation cause decreased mean arterial and diastolic blood pressures. Potent chronotropic effect may cause increased systolic blood pressure
