Quiz 1: Vasoconstrictors and DIrect Vasodilators Flashcards
How is Norepinephrine made?
- Dompamine enters the synaptic vessel
- Dopamine beta Hyroxylase converts dopamine to Norepiniphrine .
- An action potential releases NE from the synaptic vessel.
Termination of Norepinephrine is done by:
- reuptake
- Dilution by diffusion
- Metabolim: Monamine Oxidae (MAO) and catechol-o0methyltranserase
List the Adrenergic receptors for the Sympathetic Nervous System?
- Alpha 1: Periphery
- Alpha 2: Central
- Beta 1: heart
- Beta 2: other smooth muscle
List the sympathetic nervous system Alpha 1 (Receptor) Postsynaptic effect on the body?
- Increase intracellular calcium
-Smooth muscle contraction
-Peripheral vasoconstriction
-Bronchoconstriction
-Inhibits Insulin secretion
Stimulate glycogenolysis and gluconeogenesis
-Mydriasis
-GI relaxatioin
List the sympathetic nervous system Alpha 2 (Receptor) Postsynaptic effect on the body?
PRESYNAPTIC IN THE PNS
- Decreases entry of calcium into the cell
- Limits the release of norepinephrine
POSTSYNAPTIC IN THE CNS
- Sedation
- Decreased sympathetic outflow
- Decreased BP
- Platelet aggregation
List the sympathetic nervous system Beta 1 (Receptor) Postsynaptic effect on the body?
INCREASE
- Heart Rate
- Conduction velocity
- myocardial contractility
List the sympathetic nervous system Beta 2 (Receptor) Postsynaptic effect on the body?
- Smooth muscle relaxation
- Peripheral vasodilitation
- Decrease in B/P
- Bronchodilitation
- Increases insulin secreation
- Increases glycogenolysis and gluconeogenesis
- Decreases GI mobility
What is the Sympathetic Nervous System?
- Thoracolumar origin (T1-T12)
- Preganglia near spinal cord
- Postganglia secret norpinephrine ->adrenergic fibers
What is the Parasympathetic Nervous System?
- Craniosacral origin 3, 5, 7, 10
- Preganglia near organs of innervation
- Postganglia secret acetylcholine (Ach) -> Cholinergic fibers
T/F: Acetylcholine activates both arms of the SNS.
TRUE
What creates acetylcholine?
- Choline + Acetyl CoA
What deactivates acetylcholine?
- Acetylcholinesterse
What are the cholinergic receptors?
- Nicotinic
- Muscarinic
_______ _________ : extended exposure to agonists reduces the number, but not their response. Results in tachyphylaxis.
- Down regulation
_______ ______ : chronic depletion of catecholamine or use of antagonists increases the number of receptors, but not their sensitivity. May account for withdrawal syndrome with beta blockers.
- Up regulation
Describe receptor Uncoupline?
- Occurs rapidly
- Inability of the receptor to bind G protein ( alter the function of the receptor)
Describe receptor Sequestration?
- Occurs more slowly
- Movement of receptors from the cell surface to intracellular compartments
Describe receptors downregulation on a cell?
- Prolonged process
- Movement of receptors from the cell surface to intracellular compartments, but then DESTROYED
What is pheochromocytoma?
-Uncontrolled release of catacolamines via a adrenal tumor which causes SNS stimulation.
T/F: a Catecholamine can be either a neurotransmitter or a hormone.
TRUE
What receptor does a catecholamine work on?
-Adrenergic receptor
What is a sympathomimetic?
-Compound that resemble catecholamines except that hydroxyl groups are not present in both the 3 and 4 posetions of the Benzene ring.
How are sympathomimetic classified?
- By their selectivity for stimulating the alpha and/or beta receptor.
Indirect acting sympathomimetics are:
- Synthetic non-catecholamines
- release endogenous neurotransmitter NE from postganglionic sympathetic nerve endings
Direct-acting sympathomimetics are:
-Catecholammines and synthetic non-catecholamines
All sympathomimetic are derived from ______.
-B phenylethylamine
Presence of ______ groups on the 3 and 4 postion of the benzene ring of the B phenylethylamine creates a CATACHOL.
- hydroxyl
Pharmacological effects of sympathomimetics for vasoconsticition effect:
-cutaneous and renal circulations
Pharmacological effects of sympathomimetics for vasodilation effect:
-skeletal muscle
Pharmacological effects of sympathomimetics for respiratory effect the lungs in what way?
-bronchodilation
Pharmacological effects of sympathomimetics for cardiac stimulation effect:
- Increased heart rate
- Increased myocardial contractility
- Vulnerability to dysrhythmias
Pharmacological effects of sympathomimetics for hepatic effect:
-glycogenolysis
Pharmacological effects of sympathomimetics modulate what hormones:
- insulin
- renin
- pituitary
Pharmacological effects of sympathomimetics for the CNS is:
Stimulation
T/F: The only time a vaopressor should be used is when the patient’s blood pressure must be increased immediately to avoid pressure dependent reduction in organ perfusion with subsequent ischemia.
TRUE
The pharmacologic response caused by a sympathomimetic is related to the _____ of the alpha and beta adrenergic receptors in the tissues.
-density
T/F: There is a direct relationship between the concentration of available sympathomimetic and the number of receptors.
FALSE (There is an inverse….)
What enzymes are responsible for inactivating the drugs containing the 3,4 dihydroxybenzene (catecholamines) structure?
- Monoamine oxidase (MAO)
- Catechol-o-transferase (COMT)
T/F: Administration of catecholamines is effective through oral, SQ, or IV routes.
FALSE (….effective through SQ and IV routes.)
Where are monoamine oxidase (MAO) primarily found?
- liver
- Kidnerys,
- GI tract
What is the best way for administration of Epi.
- SQ
- IV
What is the best way for administration of Dopa. or Norepi.
-IV
Metabolism of synthetic noncatecholamines would be:
- lack the 3 hydroxyl group
- Metabolism is often SLOWER that that of catechos
- Inhibition of MAO may prolong their duration of action.
- Patients on MAO inhibitors may manifest exaggerated responses when treated with synthetic non-catecholamines.
Metabolism of a synthetic non-catecholamine is metabolized by ______ and not by _______.enzymes.
- MAO
- COMT
Vasoconstrictors increase aterial _____ and ____ as well increase venous ______.
- resistence
- afterload
- return
What would be some reflex changes seen with vasoconstrictors?
DECREASE
- Heart Rate
- conduction
- contractility
What noncardiac effects are seen with vasoconstictors?
- Bronchodilate
- Glycogenolysis
- Insulin, renin, pituitary hormone
- CNS stimulation
What would be the indication for a vasconstrictor?
-Decrease in arterial resistance
After administering a proper dose of a vasoconstrictor iatrogenic affects can be seen in the patient. What would be the proper action?
-All is well….Iatrogenic means the results of administering the vasoconstrictor
What would be contraindications/complications for using vasoconstrictor:
- Worsen LV failure
- exacerbate RV failure
- Decrease renal blood flow
- Can mak hypovolemia
What would be the three natural catecholamines?
- Epinephrine
- Norepinephrine
- Dopamine
Epinephrine stimulate what receptors?
- Alpha 1
- Beta 1
- Beta 2
T/F: Epinephrine is the most potent activator of Alpha 1 receptor.
TRUE
What does epinephrine increase?
- lipolysis,
- glycogenolysis
What does epinephrine decrease?
insulin
T/F: Epinephrine will still decrease renal blood flow even in the ABSENCE of changes in the systemic BP.
TRUE
Epinephrine stimulates renin release which is a ____ effect.
-indirect
A low dose of epinephrine of 1-2 mcg/min will:
-stimulate alpha 1 receptor at the skin, mucosa, and hepatorenal system WHILE beta 2 receptors are stimulated in the muscle
During a low dose of epi (1-2 mcg/min) does the MAP remain the same?
YES
Giving an intermediate does of epinephrine (4 mcg/min) will cause:
INCREASE (BETA 1)
- Heart rate
- Contractility
- Cardiac output
T/F: An intermediate does of epinephrine may lead to dysrhythmias (PVC) in sensitized myocardium.
TRUE
High dose of epinephrine (10 mcg/min) would cause:
-vasoconstriction of cutaneous, splanchnic and renal vascular beds.
T/F: Epinephrine at high doses has no effect on cerebral arterioles.
TRUE
What reflex could be seen with high doses of epinephrine?
-Bradycardia
What is Racemic Epinephrine made up of:
- Levo
- dextrorotatory isomers
T/F: Norepinephrine effect beta more than it does alpha.
FALSE
Norepinephrine is a potent vasoconstrictor of the _______, ___________, and ___________ vascular beds.
- renal
- mesenteric
- cutaneous
What refractory can be seen with norepinephrine?
- HYPOTENSION
- (bradycardia)
At high does why may C.O. be decreased?
- Increased afterload
- baroreceptor-mediated reflex bradycardia
T/F: Dopamine effects both the alpha and beta receptors.
TRUE
Dopamine over 5 mcg/kg/min causes ______ to be released.
-noriepinephrine
Dopamine at 10 mcg/kg/min _____ effects start to predominate.
Alpha
T/F: Dopamine has NO effect on pulmonary status.
TRUE
What CNS effects will be seen with dopamine:
INCREASE -mania DECREASE -Schizophrenia, ADHD, PG -prolactiv secretion -D2 inhibition
What monitors will be needed with dopamine:
-BP, HR, MAP, urine output, mental status
T/F: Ephedrine is an endogenous catecholamine.
FALSE (…..is a synthetic noncatecholamine.)
Ephredrine principle effect is stimulating the releases of _________
-noriepinephrine
Ephredrine principle mechanism is increased ______ ________.
-myocardial contractility
Ephedrine causes _________ greater than ________ constriction increases _______ and with ________ heart rate and myocardial __________, INCREASES CARDIAC OUTPUT (beta 1 receptor)
- venoconstriction
- arteriolar
- preload
- Increased
- contractility
T/F: Ephedrine preserves/increases uterine blood flow.
TRUE
Ephedrine is a _______ smooth muscle relaxant.
bronchial
Ephedrine compared to epinephrine has a ____ BP response, but a ______ duration.
-less
longer
What are some side effects of ephedrine.
- HTN,
- insomnia,
- urinary retention,
- headache,
- weakness,
- tremor,
- palpitation,
- psychosis
Phenylephrine is a _______ ____ catecholamine.
-synthetic non
Phenylephrine is a increases _____ more than _______.
- Preload
- afterload
T/F: Phenylephrine has a small beta 1 effect.
TRUE
What are other uses of phenylephrine.
- drug induced priapism
- mydriatic agent
- nasal decongestant
Phenylephrine causes reflex ________.
-bradycardia
Phenylephrine _________ renal and splanchnic blood flow
decreases
Phenylephrine _______ pulmonary artery resistance and pressure.
Increases
T/F: Phenylephrine has no dysrrhythmias as a direct effect.
TRUE
Phenylephrine ______ Right to Left shunt in Tetrology of Fallot.
REVERSES
Unlike catecholamine, effects of arginine vasopressin are _______ during hypoxia and severe acidosis.
preserved
Vasopressin is used to preserve the ___________ homeostasis in patient with advanced vasodilitory shock.
cardiocirculatory
Vasopressin advantages over epinephrine are:
- does not increase myocardial oxygen consumption
- may work better in acidic environment patients
What causes the cardiac dysrhythmias in vasoconstrictors?
Beta Stimulation
Pure alpha agonists can _____ baroreceptor reflex-mediated ________ and possible _________ CO.
- activate
- bradycardia
- decrease
Antihypertensives may _______ the pressor response to indirect acting drugs or _______ the response to direct acting drugs (denervation hypersensistivity)
- decrease
- enhance
Cocaine interferes with reuptake of catecholamines. Both exogenous and endogenous catecholamines exhibit ________ effects.
enhanced
Acute toxicity of cocaine may best be treated with ________ blockade.
adrenergic
Labetalol with alpha and beta effects
Natural weight loos products may contain “ma huang” which is ______.
ephedra
T/F: Ephedra contains ephedrine and psuedoephedrine.
TRUE
How long do you want a person to stop taking “ma huang” before surgery?
24 hours
T/F: Long term use of “ma huang” (ephedra) results in tachyphylaxis from depletion of endogenous catecholamine stores and may contribute to perioperative hemodynamic instability and cardiovascular collapse.
TRUE
Phentolamine treats:
-Skin necrosis secondary to norepinephrine, dopamine and epinephrine
What receptors does phentolamine work on and is it an agonist or antagonist?
- Alpha 1 and 2
- Antagonist
What is idiopathic hypertension:
- over activity of the ANS
- Interaction with the Renin angiotensin system
- factors related to the sodium homeostasis and intravascular volume
What would cause perioperative hypertension:
- inadequaate anesthesia
- airway manipulation
- hypercarbia
- hypoxia
- medications
- aortic cross clamp
- hypervolemia
- hypothermia
- pain
What pre-existing disease would cause perioperative hypertension:
- pheochromocytoma
- Hyperthyroid
- autonomic hyperreflexia
- malignant hyperthermia
- intracranial hypertension
- renal disease
- poorly controlled hypertension
What are the complication of perioperative hypertension?
- CVA
- MI
- ischemia
- LV dysfunction
- arrhythmias
- increased suture tension
- hemorrhage,
- pulmonary edema
- cognitive dysfunction
What is the primary cause of perioperative hypertension?
-Increased sympathetic discharge with systemic vasoconstriction
What are the mechanism of action for vasodilators:
- Direct smooth muscle dilatation (Calcium channel blocker and nitrates)
- Alpha 1 antagonists (prazosin and labetalol)
- alpha 2 agonists (clonidine and alpha-methyldopa)
- A.C.E. inhibitors (captopril ad enalapril)
What would be the site of action for vasodilators;
- arterial dilators
- venodilators
- Balanced vasodilators
Pure arterioe dilator causes minimal effect on _____.
preload
“Pure” venodilators are ___ available. NTG acts primarily on the venous circulation, but also affects ______.
- NOT
- arterioles
Balanced vasodilator (SNP) decreases ______ and ________.
- afterload
- preload
T/F: Inhaled NO may be only “pure” pulmonary vasodilator.
TRUE
Prostaglandin E1 (PGE1) is excellent pulmonary ________, but also causes systemic _______ requiring noriepinephrine to maintain systemic B/P.
- vasodilator
- hypotension
What is reflex effect of using a vasodilator:
increase heart rate
What will vasodilators do to the hear arterioles?
-cause coronary steal
How much artery perfusion to the LEFT VENTRICLE occurs during diastole?
70 - 90%
T/F: Aortic systole pressure governs perfusion.
FALSE (Aortic diastolic….)
Nitroglycerin preferentially dilates _______ vessels and ______ more blood toward ischemic zones.
- conductace
- directs
What are the vasodilators?
- hydralazine
- nitroglycerine
- Sodium nitroprusside
Is Hydralazine a direct acting or indirect acting arterial vasodilator.
-direct acting
What effects does hydralazine have on the cardiovascular system?
INCREASES
- heart rate
- contractility
- cardiac output
- stroke volume
- renin activity
- fluid retention
- MYOCARDIAL OXYGEN DEMAND
DECREASES
-B/P (diastolic > systolic)
What type of patient do you want to avoid administering hydralazine to.
- CAD
- Increased ICP
- Lupus
What are the advantages of hydralazine?
- maintains/increases cerebral blood flow
- increases CO
- Increases Stroke volume
What are the disadvantages of hydralazine?
-Reflex tachy
-
Nitroglycerine causes a release of ____ _____ for ___- specific relaxation of the vascular smooth muscle.
- nitric oxide
- non
What does nitroglycerine do to the coronary arteries?
- relaxes
- relieves spasms
What are some non-cardiac effects of nitroglycerine?
- dilates meningeal vessels
- Decrease renal blood flow with decrease BP
- dilates pulmonary vessels
Nitroglycerine is metabolized by ___________ nitrate reductase in the ______?
- glutathione
- LIVER
A nitrite ion oxidizes Hgb to ___________.
methemoglobin
Nitroglycerine tolerance in _______ vessels can occur with chronic administration but not in the venous vessels.
- arterial
- venous
What are warnings and contraindications for nitroglycerine?
- PDE5 (Viagra, cialis, ravashia)
- narrow angle glaucoma
- head trauma, cerebral hemorrhage
- severe anemia
- hypotension
Does sodium nitroprusside directly or indirectly vasodilate arteries and veins?
-DIRECTLY
With abrupt discontinuation of sodium nitroprusside can cause ______ _______ and _________.
- reflex
- tachycardia
- hypertension
Sodium nitroprusside causes a _____ in renal blood flow.
Decrease
Sodium nitroprusside causes pronounced hypotensive effects with ______ and _______ ________.
- spinal
- general
- anesthesia
T/F: Sodium Nitroprusside metabolites are active and increase the effects.
FALSE (….are not active….)
What are some warning and contraindication for sodium nitroprusside?
- congenital optic atrophy
- hypovolemia
- compensatory HTN (AV shunting and aortic coarctation)
- Severe renal/hepatic impairment
What type of toxicity could sodium nitroprusside cause:
cyanide
What is the presentation of cyanide toxicity:
- hypotension
- blurred vision
- fatigue
- metabolic acidosis
- pink skin
- absence of reflexes
- faint heart sounds
What are the thiocyanate levels: -
-therapuetic 6 - 29
-toxic 35-100
fatal >200
What are the advantages of sodium nitroprusside:
- immediate onset
- short duration
- reduced myocardial O2 demand
What are the disadvantages of sodium nitroprusside:
- reflex tachycardia
- cyanide toxicity
- intrapulmonary shunting
- precipitous drop in BP
- photodegradation
- methemoglobinemia
- coronary steal
- Enhanced bleeding
- cerebral vasodilator
