Vasoconstriction

Question 1

amides in general characteristic

Answer 1

vasodilation except cocaine - so they would have a short duration if no addition of vasoconstriction

Question 2

big difference between LA drug and other drugs

Answer 2

LA - has to stay in area - other drugs go to different target areas

Question 3

vasoconstrictor - general and what are its advantages

Answer 3

*agent that causes narrowing of the blood vessels
advantages:
1. decrease blood flow to the site of injection
2. prolong and increase the depth of anesthesia
3. reduce the toxic effect of the drug
4. render the area of injection with less bleeding

Question 4

reduce the toxic effect of the drug?

Answer 4

a vasoconstrictor has this characteristic

Question 5

same anesthetic max dosage with and without vasoconstriction

Answer 5

less toxic with vasoconstrictor

Question 6

chemical structure of vasoconstrictor

Answer 6

chemically identical / quite similar to the sympathetic nervous system mediators epinephrine and norepinephrine

*resemble the response of adrenergic nerves to stimulation and are classified as sypathomimetic nerves or adrenergic

Question 7

catecholamines

Answer 7

ones that we mainly use - 
epinephrine 
norepinephrine 
levonoproterenol 
isoproternol
dopamine

Question 8

noncatecholamines

Answer 8

still vasoconstrictors but not ones we clinically usually use 
amphetamine
methamphetamine
ephedrine
phenylephrine

Question 9

direct acting drugs

Answer 9

exert their action directly on adrenergic receptors IN THE POST SYNAPTIC

Question 10

Indirect Acting drugs

Answer 10

drug enhances release of catecholamine norepinephrine from adrenergic nerve terminals

neurotransmitter release from the vesicles at the pre-synaptic area

*Tachyphylaxis could occur? or associated with this method of action

Question 11

mixed acting drugs

Answer 11

act on the pre-synaptic area and enhance release from vesicle - from the adrenergic nerve terminals and also work directly on the post synaptic receptors

Question 12

vasoconstrictors we use - epi and norepi function in what type of method/action

Answer 12

Direct acting – stimulate the receptors at the post synaptic area

Question 13

Two types of adrenergic receptors

Answer 13

Alpha –> vasoconstrict

Beta –> vasodilate

Question 14

activation of alpha receptor by sympathomimetic drug

+ alpha 1 vs alpha 2

Answer 14

stimulates contraction of smooth muscle in vessels = vasoconstrict
alpha 1 = EXCITATORY post-synaptic
alpha 2 = INHIBITORY
- so NE release and Ach release would decrease in release

Question 15

Beta 1 activation causes

Answer 15

Vasodilate and bronchodilatation and cardiac stimulation

increase in contractility of the heart and lipolysis by small intestine

Question 16

Beta 2 activation causes

Answer 16

Vascular beds - VESSELS - produces vasodilation

Bronchi - bronchiodilatation * = relaxation

Question 17

potential contraindication of patient taking non-selective beta blockers and using vasoconstrictors?

Answer 17

*stimulation of B receptors is BLOCKED - so vasodilation or bronchodilatation does NOT occur

this will block the activation of dilation in the VESSELS of the smooth muscle/heart so could increase HR too much in these patients
- giving a vasoconstrictor and wont have the effect of dilation produced normally by the activation of these receptors

Question 18

overview of administration of epinephrine

Answer 18

Stimulate alpha receptors and beta receptors

alpha – increase in contractility, gluconeogensis in liver and salviary gland secretion

beta - vasodilation of smooth muscle and bronchiodilation

Question 19

epinephrine works mostly on?

Answer 19

alpha and beta receptors

Question 20

norepinephrine works mostly on what receptors?

Answer 20

mainly alpha

Question 21

levonordefrin works on what receptors?

Answer 21

contraindicated - see both occurring

Question 22

specific characteristics of epinephrine + what is added to it and what are those implications?

Answer 22

as the acid salt it is highly soluble in water
*addition of sodium bisulfite is added to delay deterioration (if allergic rxn occurs it is usually due to this aspect of the drug)

synthetic + secreted from adrenal medulla

acts DIRECTLY on alpha and beta receptors

Question 23

which receptors predominate with administration of epinephrine?

Answer 23

Beta predominates - which is vasodilation HOWEVER AT HIGH CONCENTRATIONS THE ALPHA predominate – which causes vasoconstriction and why we use it for this with administration of LA (high concentration in area we inject)

but at lower concentrations - beta receptors will dominate

Question 24

marked increase in systolic pressure when?

Answer 24

epinephrine with alpha receptors

Question 25

myocardial oxygen consumption?

Answer 25

increases when heart is working more a systemic effect of epinephrine - increases cardiac output with HR and SV so more oxygen is needed to the heart

Question 26

epinephrine effect on respiratory

Answer 26

is a potent dilator B2 effect of the smooth muscle of the bronchioles

Question 27

termination of action of epinephrine

Answer 27

1. reuptake by the adrenergic nerves 2. inactivation in the blood by the enzyme catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO), both which are present in the liver

Question 28

COMT and MAO

Answer 28

enzymes that are present in the LIVER - and these break down and elimate the action of epinephrine

Question 29

max dosage of epinephrine in normal healthy pt.

Answer 29

.2mg per appointment | 10 ml per 1:50,000 dilutoin - 5 cartridges

Question 30

max dosage of epinephrine in ASA III or IV

Answer 30

0.04 mg per appointment

Question 31

side effects and overdose of epinephrine

Answer 31

CNS stimulation - increases fear, anxiety, tension, resltessness, headache, tremor, weakness cardiac dysrhythmias increased systolic angina

Question 32

norepinephrine - specific +aka

Answer 32

AKA - levarterenol relatively stable in acid solution, deteriorating on exposure to light and air acetone-sodium bisulfite added to retard deterioration natural and syntehtic forms actions are 90% alpha and 10% beta

Question 33

systemic effects of norepinephrine

Answer 33

DECREASED HR - because we increased systolic and diastolic pressures so maintain *increased total peripheral resistance most noteable are the increases in systolic (greatest variation) and diastolic and mean arterial pressure with compensatory effect of decreased HR

Question 34

norepinephrine on respiratory system

Answer 34

does NOT relax bronchial smooth muscle as does epinephrine

Question 35

termination of norepinephrine

Answer 35

reuptake and its oxidation by MOA + exogenous norepinphrine is inactivated by COMT

Question 36

clinical applications of norepinephrine

Answer 36

in LA as vasoconstrictor + helps with management of hypotension because increases peripheral resistance

Question 37

max dose of norepi in healthy patient

Answer 37

0.34 mg / appointment

Question 38

max dose of norepi in ASA III or IV patient

Answer 38

0.14 mg / appointment

Question 39

Levonodefrin

Answer 39

synthetic vasoconstrictor direct alpha receptor - stimulation is 75% with some beta activity (25%) systemic effects are similar to epinephrine but to a lesser degree

Question 40

weakest vasoconstrictor used in dentistry?

Answer 40

Phenylephrine Hydrochloride - soluble in water - direct alpha receptor - exerts little or no B action on the heart

Question 41

Felypressin

Answer 41

Synthetic analogue of the antidiuretic hormone vassopressin acts as a direct stimulant of vascular smooth muscle *no direct effect on the myocardium - which could be of benefit

Question 42

relative contraindications

Answer 42

patients with more significant cardiac disease patients with certain noncardiovascular diseases (thyroid dysfunction, diabetes, sulfite sensativity) patients receiving MAO inhibitors(drug would not be eliminated in normal fashion), tricyclic antidepresants and phenothiazines