Endogenous Catecholamines and D1 Agonists Flashcards
What binds alpha and beta 2
Epinephrine
What binds alpha and beta 1 > 2
Norepinephrine
What binds D, alpha and beta
Dopamine
What binds D1
Fenoldopam
DOC for patients in anaphylactic
Epi
Potent vasopressor at high doses
Epi
Cause bradycardia
Norepi (indirect M2)
Limited therapeutic value, but can treat shock
Norepi
DOC for cardiogenic and hypovolemic shock
Dopamine
Why is dopamine better than norepi for shock
DA preserves renal blood flow
Effects of high dose epi
Increase BP
+ve chronotropic/ionotropic (beta 1)
Vasoconstriction (alpha 1)
Increase CO and O2
Effects of low dose epi
Decrease PVR
Increase systolic, decrease diastolic
No change in MAP
Tachycardia (beta 1)
SM effects of epi
Bronchodilation (beta 2)
Relax GI with contracted sphincters
Relax detrusor (beta 2), contract sphincter (alpha 1)
Prostate SM contraction
Metabolic effects of epi
Hyperglycemia
Lypolysis (beta 3)
How does epi cause hyperglycemia
Increase glycogenolysis and glucagon release (beta 2)
Net inhibition of insulin secretion (alpha 2 inhibits, beta 2 enhances)
What effect does epi have in glaucoma
Decrease aqueous humor production
How do you treat asthma attacks with epi
Combine with local anesthetics to increase duration
Causes Vasoconstriction
Epi (alpha 1)
Norepi (alpha 1)
Effects of norepi vasoconstriction
Increased PVR
Increased SBP/DBP and MAP
Induces hyperglycemia less potent than epi
Norepi
Function of DA
Central regulator of movement
CVS effects of DA
Low dose - vasodilate (D1): renal, mesenteric, coronary
How does DA treat shock
Increase GFR, RBF, Na+ excretion
Ie. preserves renal function
What is the inotropic effect of DA
Intermediate contraction (beta 1) Increasing NE release
Effect of DA on BP
Increase SBP
Effect of high concentration DA
Alpha 1 vasoconstriction
Effect of Fenoldopam
Peripheral vasodilation
What is used for short term management of inpatient HTN
Fenoldopam
Administration of Epinephrine
IV emergency
SC, ET tube, inhalation, topical eye
Why don’t you give epi orally
Inactivation in gut
Why is DA ineffective orally
Metabolized by MAO and COMT
How is Fenoldopam administered
IV
Does DA cross BBB
No
Notable AE of epi
Tremor
ICH due to increased BP
Arrhythmias - Digitalis pts
Pulm edema
What causes kidney shutdown
Norepi
DA overdose
Sympathomimetic Sx
Why is DA nausea, HTN and arrhythmia short-lived
Rapid metab to HVA
Does Epi enter CNS
No, polar
How is epi metabolized
COMT and MAO
Makes VMA and metanephrine
How does hyperthyroid affect epi
Enhance CV actions
How does cocaine affect epi
Prevent reuptake
How do beta blockers affect epi
Cause predominate alpha effects - increase TPR and BP
What counteracts local action of norepi
Baroreceptor reflex
How do you block baroreceptor counteraction of norepi
Atropine
