Pharm 9.2 Flashcards
Epinephrnien on SM in GIT
relaxation, peristalsis is reduced and sphincters are constricted
Epi on SM in Bladder
trigone and sphincter contricted (alpha 1 rec), detrusor relaxed (beta 2), net effect is urinary retentino
Epi on SM in uterus
relaxation at term (tocolysis - lysis of contraction of the uterus so no risk of premature delivery)
dialation of puple
alpha 1 agonist on radial muscles
constriction of pupil
M3 muscaranic agonis on sphincter pupallae
uses of Epinephrine
bronchospasm, anaphylactic shock, local anaesthetics, glaucoma, cardiact arrest
Epi in bronchospasm
primary drug used in emergency due to acute attacks of asthma
Epi in anaphylactic shock
drug of choice, can increase BP in deadly hypotension and increase respiratory exchange
what is the durg of choice in anaphylactic shock
epinephrine
epi with local anaesthetics (adjunct)
1/100, 000 parts, increase duration of action of local anaesthetic due to alpha 1 and beta 2 effects (low dose beta 2) (Epinephrine + Lidocain)
epi with glaucoma (open angle)
decrease IOT due to decreased production of aqueous humor by vasoconstriction of ciliary body blood vessels (2% eyedrop)
Prodrug for glaucoma
Dipivefrin - rarely used
epi with cardiac arrest
to restore cardiac rhythm in patients with cardiac arrest or heart block regardless of cause
Epinephrine adverse effects
palpitation, restlessness, tremors, increase in BP, arrhythmia, cerebral hemorrhage (due to marked elevation of BP)
when is epinephrine contraindicated
angina pectoris
epinephrine interactions
hypertyroidism, cocaine, diabetes, beta blockers
epinephrine, norepinephrine, and dopamine are orally
inactive
duration of action of epinephrine
rapid onset but a brief duration of action (due to rapid degradation)
epinephrine and norepinephrine are degraded by
MAO and COMT of the intestine wall and liver
treat hyperthyroidsm by
using a beta blocker to block the hyper adrenergic state
how does cocain affect epinephrine
inhibits its reuptake
betablockers given with epinephrine
only left wth alpha 1 effects causing vasoconstriciton
Epinephrine can be given
IV, intracardiac, inhalational, subcutaniously, endotracheal tube, or topically
Norepinephrine activates
all but BETA 2, more alpha effects causing vasoconstirction, reflex bradycardia
NE on TPR
inc TPR due to vasoconstriction of most of the vascular beds
NE on systolic and diastolic BP
increase
NE on pulse rate
decrease pulse rate (reflex bradycardia) due to inc in BP, reflex rise in vagal activity by stimulating barroreceptors, decrease heart rate, decrease pulse rate
If atropine is given before NE
it will result in tachycardia
NE on alpha 1 receptors
inc TPR, inc BP (potential reflex bradycardia)
NE on beta 1 receptors
inc HR, inc SV, inc CO, inc pulse pressure
Difference btw high does epinephrine vs NE in reversing hypertension
if you are to use an alpha 1 blocker to reduce vasoconstirctin, epinephrine continues to work on beta 2 receptors that results in hypotension, but NE do not work on beta 2 receptors
Isoproterenol
direct acting synthetic catecholamine, nonselective beta agonist
isoproterenol on beta 1 receptors
increased contractility and heart rate
isoproterenol on beta 2 receptors on heart
decrease in TPR, decrease in mean BP
isoproterenol overall effect on heart
systolic blood pressure does not fall significantly as diastolic due to beta 1 receptor action so the pulse pressure decreases
activation of beta 2 in the lungs and GI and uterus
relaxation of SM
Isoproterenol is used in
bronchospasm, heart block, bradyarrhythmias
dopamine acts on
D1, D2, alpha, and beta receptors
D1 in the renal and mesenteric blood vesses
dialates - most sensitive at low dose
moderate high dose dopamine
positive iontropic action on the heart by beta 1
high dose dopamine
vasoconstriction on alpha 1 receptors
as the dose increases the binding of dopamine follows
D1 –> beta 1–> alpha 1
the shape of the dose response for natriuresis curve of dopamin is
an inverted U
natrieurisis and dopamine
both natriuretic and diuretic
dopamine increases
myocardial contractility, RBF, GFR, sodium excretion, urine output
Dopamine in cardiogenic shock is the drug of choice bc
increases BP by stimulating heart (beta 1), increasing perfusion to kidney and splanchnic areas (through D1 receptors) by vasodialation, increases blood flow to the kidney, increases GFR, increases Na+ diuresis, prevents kidney shutdown
Dopamine agonists
fenoldopam, dopexamine
dobutamine is a
selective beta1 agonsit, increases the force of contraction of the heart, with little change in HR,
why is do butamine a major advantage over other sympathomimetic drugs
used in CCF, MI with failure bc it increases CO without elevating the oxygen demand of myocardium - am major advantage over other sympathomimetic drugs (which work at the expense of oxygen)
alpha 1 selective agonists
phenylephrine, methoxamine
Phenylephrine is a
specific alpha 1 agonist direct acting noncatecholamine, increases the mean blood pressure viea basoconstriction with minimal effect on pulse pressure, increasein BP can elicit reflex bradycardia, no direct effect on heart
Phenylephrine is used in
nasal decongestion, mydriasis, to retard absorption of local anesthetics, to raise BP and to terminate episodes of supraventricular tachycardia (esp Methoxamine)
alpha 2 selective agonists
clonidine, methyldopa
clonidine is a
alpha 2 selective agonist
clonidine acts centrally to produce
inhibition of sympathetic vasomotr centers, decreaseing sympathetic outflow to the periphery
clonidine bioavailability
excellent (transdermal patches also available)
Clonidien adverse effects
dry mouth, sedation, bradycardia, sexual dysfunction, rebound hypertension (following abrupt withdrawal of clonidine)
uses of clonidine
used in hypertension (to lower BP because of its central actions), also used to minimize the symptoms associated with opiates or benzodiazepines withdrawal
other alpha 2 agonists
guanfacine, guanabenz, methyldopa (HTN in pregnancy), Tizanidine (spasmolytic)
Methyldopa is used for
hypertention in pregnancy
Tizanidine is used as a
spasmolytic
topical direct acting sympathomimetics
naphazoline, oxymetazoline, xylometazoline
Naphazoline is used as
a topical vasoconstrictor - nasal decongestant
Oxymetazoline is used to
reduce congestion and swelling of th nasal mucosa - nasal decongestant
xylometazoline is used as a
nasal decongestant
indirect acting sympathomimetci drugs
amphetamine, tyramine, ephedrine (mixed action)
amphetamine is a
noncatecholamine sympathomimetic drug
amphetamine function
increases the release of NE, dopamine in synaptic spaces
Amphetamine is taken
orally
Amphetamine and CNS
has prominent CNS stimulatory action, increases alertness, concentration and wok capacity
Amphetamine on RAS
activates reticular activating system producing insomnia
Amphetamine on CVS
increases BP and HR
Therapeutic uses for amphetamine
CNS stimulant in the treating ADHD, Narcolpecy (esp Modafinil, a new amphetamine substitute), Obesity (appetite control/appetite suppression)
Tyramine releases
large amounts of stored CA from nerve terminals
is Tyramine used clinically
no
Tyramine is found in
fermented foods, such as aged/riped chees, meats, chicken liver, pickled or smoked fish such as anchovies or herrings, and red wines
Tyramine is inactivated by
MAO in the gut
Tyramine can participate in
the “cheese reaction”
Cocain use
local anesthetic agent, having ability to block uptake of NE in the adrenergic neurons; concequently NE accumulates in the synaptic space resulting in enhancement of sympathtic activity. Also a CNS stimulant and drug of abuse.
Mixed acting drugs
ephedrine, pseudoephedrine
Ephedrine/pseudoephedrine is an
alkaloid from the plant Ephedra vulgaris
repeated injections of ephedrine produce
tachyphylaxis
Ephedrine is resistnat to
MAO and COMT
Ephedrine is effective taken
orally and crosses the BBB - CNS stimulation
Ephedrine uses
bronhial asthma (not really no) and nasal congestion
Phenylpropanolamine is an
alpha agonist
Phenylpropanolamine is used as a
nasal decongestant, may cause severe hypertension
Phenylpropanolamine is unsafe because
it causes strokes in women
Drugs having selective beta 2 action
albuterol, pirbuterol, salmeterol, foroterol, terbulatine, metaproterenol
Tocolytic agents
Ritodrine, Terbutaline (beta 2 agonist)
Tocolytic agents work by
relaxing the pregnant uterus and supressing premature labor
chart on 108
look at it, mostly tells you cateholamines have no oral activity, but other sympathomemetics do except pehnylephrine and cocaine and the sympathomimetics take hours to work, while catecholamines take minutes
Pressor agents
NE, Dopamine
Cardiac stimulants
Epinephrine, Isoproterenol, Dobutamine
Bronchodialators
Epinephrine, Isoproterenol, Albuterol
Nasal decongestants
Ephedrine, Pseudoephedrine, Phenylpropanolamine, Oxymetazoline, Xylometazoline
CNS Stimulants
Amphetamine, Ephedrine
Uterine relaxants
Isoxsuprine, Terbutaline, Ritodrine
