Sympathomimetic- Ephedrine Flashcards
Ephedrine bottle concentration
50mg/ml
indirect acting synthetic sympathomimetic that stimulates alpha and beta adrenergic receptors
ephedrine
which receptors does ephedrine DIRECTLY stimulate
alpha
which neurotransmitter does ephedrine INDIRECTLY stimulate the release of
release of endogenous NE
why can we give ephedrine PO
resistant to metabolism by MAO in the GI tract
how much ephedrine is excreted in the urine unchanged
40%
how is ephedrine metabolized
deaminated by MAO in the liver
why is IM ephedrine clinically acceptable
local vasoconstriction is insufficient to delay systemic absorption or lead to tissue injury
what is responsible for the prolonged duration of action of ephedrine
slow inactivation and excretion of ephedrine
does ephedrine increase blood sugar
no hyperglycemia
eye effects with ephedrine
mydriasis
does CNS stimualation occur
yes
ephedrine dose
5-10mg
why WAS ephedrine considered the better choice for parturients?
Was considered the preferred sympathomimetic for parturients with decreased systemic BP due to spinal or epidural anesthesia. Animal studies demonstrated uterine blood flow was not greatly altered
why do we prefer phenylephrine over ephedrine for parturients
Phenylephrine is associated with a higher umbilical artery pH at delivery.
Phenylephrine by infusion during a C-section to maintain maternal SPB at baseline is associated with a lower incidence of fetal acidosis than is ephedrine
if sympathetic nervous system blockade is present or hypotension from regional anesthesia or inhaled or injected anesthesia, what medication is commonly selected to increase BP
ephedrine
compared to EPI what is ephedrine onset
slow compared to EPI
why do we give ephedrine during coryza
decongestant effect accompanying oral administration produces relief from colds
what is the antiemetic dose of ephedrine
0.5mg/kg
what is ephedrine compared to as an antiemetic
droperidol
what is the benefit to giving ephedrine over droperidol
less sedation
what is the chronic oral form of ephedrine used for
bronchial asthma because of its bronchodilating effects by activating beta 2 adrenergic receptors
iv ephedrine increase what cardiovascular effects
SBP, DBP, HR and CO
what two systems blood flows are decreased with ephedrine
renal and splanchnic
what two systems does see increased blood flows with ephedrine
coronary and skeletal muscles
ephedrine increases BP what is the response onset and duration compared to epi
less intense onset and last 10 times longer
ephedrine effects on SVR
altered minimally b/c vasoconstriction is some vascular beds is offset by vasodilation (b2 stimulation) in other areas
ephedrine alpha CV effects
peripheral arterial and venous vasoconstriction
ephedrine beta CV effects
increase myocardial contractility
second dose of ephedrine produces a less intense systemic BP response than first dose due to what mechanism
tachyphylaxis
tachyphylaxis to ephedrine involves which receptor
alpha receptor inhibition
in a beta blocked patient ephedrine may resemble response more typical to which receptor activation
alpha adrenergic receptor stimulation
