Adrenergic Stimulants: Catecholamines + Ephedrine Flashcards
NE has little effect on
B2
NE is taken
IV due to very short duration of action
effect of NE is primarily to
vasoconstriction –> increased BP (some reflex bradycardia will slow HR)
why does NE have little effect on pulse pressure?
both diastolic and systolic BP increase
when is NE used
severe hypotensive crisis
side effect of NE at injection site
necrosis due to vasoconstriction
NE causes CO
to remain unchanged or decrease
HR decreases but SV increases
when would NE caused increased HR
when given with atropine, which would block the vagal baroreceptor reflex
NE causes ___________ to organs
decreased blood flow
kidney, liver, spleen
SV and coronary flow ______ when NE is given
increase
NE stimulates _______ receptors
a1
B1
(little effect on B2)
Epi stimulates ________ receptors
Alpha
B1
B2
how to take epi
IV or SC injection
short duration of action due to rapid metabolism
effects of epi depend on
dose administered
epi effects on heart
positive inotrope and chonotrope (B1)
epi effects on BP
- diastolic and systolic go up due to alpha stimulation
2. diastolic goes back down due to B2 mediated dilation of skeletal blood vessels —> increased pulse pressure
epi effects on BP at high doses
diastolic pressure increases as alpha receptors in skeletal muscle blood vessels are stimulated
epi effect on blood glucose
increases:
- B2 - glycogenolysis
- a2 - decreased insulin secretion
epi effect on renin
increased by B1 –> contributes to increased vasoconstriction
epi effect on free fatty acids
Increased by lipolysis B3
low dose slowly given epi will
increase HR (little reflex slowing since mean BP stays the same) decrease renal blood flow
high dose rapidly given epi will
increase BP ALOT
BOTH systolic and diastolic
IF mean BP increases –> reflex bradycardia
rare emergency treatment of asthma
epi (bronchodilation by B2)
EMERGENT indications for epi
- anaphylactic shock (restore BP, decrease bronchospasm/congestion/angioedema, reverse cardiovascular collapse)
- MI
- Complete heart block
other uses for epi
- local anesthetics: vasoconstriction decreases diffusion of the drug away from injection site
- glaucoma (alpha stimulation, guess beta stimulation doesn’t matter much)
general side effects of epi
tremor
throbbing HA
increased BP
tachycardia
effects of epi in pt with CAD
angina due to increased O2 consumption/cardiac work
really bad complications from extreme vasoconstriction caused by high dose epi
cerebral hemorrhage
ventricular arrhythmia
contraindications to epi use
BETA BLOCKERS
alpha agonist effect on vasoconstriction would go unopposed – > severe htn
ephedrine receptor effects
mixed acting, alpha and beta receptors
SIMILAR TO LOW DOSE EPI
also increases NE
ephedrine vs epi
ephedrine has a longer duration of action but less pronounced effects.
ephedrine has high bioavailability
how is ephedrine excreted and how can excretion be accelerated
urine
acidify the urine
drug similar to ephedrine found in weight loss supplements which is off the market due to deaths from htn
ephedra
drug similar used in OTC decongestants and weight loss drugs → hemorrhagic stroke in women. now off market
phenylpropanolamine
