Pain Control, 9/1/11

Front 1

What are vasoconstrictors?

Back 1

an agent that causes narrowing the blood vessels.


prolong and increase the depth of anesthesia
reduce the toxic effect of the drug
render the area of injection with less bleeding
decrease blood flow to the site of injection

Front 2

Describe the chemical structure of vasoconstrictors

Back 2

chemically identical or quite similar to the sympathetic nervous system mediators epinephrine and norepinephrine
resemble the response of adrenergic nerves to stimulation and they are classified as sympathomimetic, or adrenergic.

Front 3

What makes a vascoconstrictors sympathomimetic?

Back 3

Based on whether or not is has a cathecholamine. if they have amine attached to aliphatic chain, they are called cathecolamines

Front 4

Name some catecholamines..

Back 4

Epi, Norepi, levonordefrin, isoproterenol, dopamine

Front 5

What are some noncatecholamines

Back 5

amphetamine
ephedrine
phenylephrine

Front 6

Direct acting drugs vs. indirect

Back 6

-exert their action directly on adrenergic receptors

indirect: release cathecholamine NE from adrenergic nerve terminals (tachyphylaxis)

Front 7

Direct acting drug names

Back 7

Epinephrine
Norepinephrine
Levonordefrin
Isoproterenol
Dopamine
Methoxamine
Phenylephrine

Front 8

Indirect acting drugs

Back 8

Tyramine
Anphetamine
Methamphetamine
Hydroxyamphetamine

Front 9

Mixed action drugs

Back 9

Metaraminol
Ephredine

Front 10

What happens if you activate alpha receptor by a sympathomimetric drug?

Back 10

produces a response that includes the contraction of smooth muscle in vessels (vasoconstriction).

Front 11

What happens if you active beta receptor? B1 and B2?

Back 11

Activation of  receptors produces smooth muscle relaxation (vasodilatation and bronchodilatation) and cardiac stimulation.
1 stimulates the heart
2 produces bronchodilatation and vasodilatation

Front 12

Describe the end effect of stimulating alpha and beta receptors by epinephrine

Back 12

alpha: increase systolic and diastolic pressure

beta: vasodilation or bronchodilation

with a beta blocker: vasodilation and bronchodilation does not occur

Front 13

What affect predominates with a low dose epinephrine? high dose?

Back 13

for low dose, Beta effects predominate so you get vasodilation.

for high dose, alpha effects predominate

Front 14

Describe teh cardiovascular dynamics of epiephrine

Back 14

Increased systolic and diastolic pressures
Increased cardiac output (CO = HR X SV)
Increased stroke volume
Increased heart rate
Increased strength of contraction
Increased myocardial oxygen consumption

Front 15

Describe the respiratory system effects of epinephrine

Back 15

Is a potent dilator (2 effect) of the smooth muscle of the bronchioles.

Front 16

Describe the termination of action and elimination of epinephrine

Back 16

Reuptake by adrenergic nerves ** most commonly done.


Inactivated in the blood by the enzyme catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO), both of which are present in the liver.

Front 17

What else do we use epinephrine for in the clinic?

Back 17

acute allergic reactions
bronchospasm
cardiac arrest
vasoconstrictor for hemostasis
vasoconstrictor for local anesthetics
to produce mydriasis

Front 18

Max amt of epinephrine you can give to someone for a normal healthy patient..?

Patient with clinically sig cardiovascular disease?

Back 18

0.2 mg per appointment

concentration may be dependent on whether you want hemostasis. ex: 1/50,000 may be better in hemostasis vs. 1/100,000.

Cardiac disease: 0.04 mg per appt.

Front 19

Side effects and overdose of epinephrine..

Back 19

CNS stimulation
increases fear, anxiety, tension, restlessness, headache, tremor, weakness
cardiac dysrhythmias
Increased systolic and diastolic pressures
angina

Front 20

Norepinephrine (Levarterenol)..
Chemical properties

Back 20

Is relatively stable in acid solution, deteriorating on exposure to light and air.
Acetone-sodium bisulfite is added to retard deterioration (preservative)

Is available in both synthetic and natural forms.
Actions are 90%  receptors and 10%  .

Mostly used in different parts of the world, but not here.

Front 21

Systemic actions of NE: cardiovasc. dynamics

Back 21

Decreased heart rate
Increased systolic pressure
Increased diastolic pressure
Unchanged or slightly decrease cardiac output
Increased stroke volume
Increased total peripheral resistance

not as good as epinephrine to activate alpha.

Front 22

NE: respiratory system actions

Back 22

Does not relax bronchial smooth muscle as does epinephrine.
It is not clinically effective in the management of bronchospasm.

Front 23

NE: termination of action and elimination

Back 23

Reuptake at adrenergic nerve terminals and its oxidation by MAO. Exogenous norepinephrine is inactivated by COMT.

Front 24

Clinical applications of NE

What are the max doses of NE in a normal healthy patient?

Back 24

It is used as a vasoconstrictor in local anesthetics and for the management of hypotension

0.34 mg per appt
cardiac pat: 0.14 mg

Front 25

What are the cardiac alterations after injection of 2% lidocaine with NE 1/50,000

Back 25

increase in SBP, DBP, and MAP, and decrease in HR.

Front 26

Levonodefrin - Neo-Cobefrin: chemical properties. Max dose?

Back 26

Synthetic vasoconstrictor
Direct  receptor stimulation (75%) with some  activity (25%)
Systemic actions similar to epinephrine, but to a lesser degree


Maximum Dosage: 1 mg per appointment
20 ml of a 1:20,000 dilution (11 cartridges)
Obtain with Mepivacaine 2% with Levonodefrin 1: 20,000 dilution

Front 27

Neo-synephrie (phenylephrine hydrochloride)

Back 27

Phenylephrine is quite soluble in water.
It is the weakest vasoconstrictor used in dentistry.
Direct  receptor stimulation (95%).
Exerts little or no action on the heart.

Front 28

Cardiovascular actions of phenylephrine hydrochloride

Back 28

Cardiovascular dynamics:
Increased systolic and diastolic
Reflex bradycardia
Slightly decreased cardiac output
Rarely associated with provoking cardiac dysrhytmias

Front 29

1. Pheylephrine hydrochloride. resp system
2. termation
3. side effects and overdose

Back 29

Respiratory system:
Bronchi are dilated but to a lesser degree.
Is not effective in treating bronchospasm.


Termination of action and elimination:
Undergoes hydroxylation to epinephrine, and then follows a similar pattern as epinephrine.
Side effects and overdose:
CNS effects are minimal
Headache and dysrhythmias have been noted following overdose.

Front 30

Phenylephrine HCL clinical apps..
max dose?

Back 30

Vasoconstrictor in local anesthetics
Management of hypotension
Nasal decongestant
Ophthalmic solutions to produce mydriasis

Max dose: 4 mg per appt for healthy pt
ASA III or 4: 1.6 mg

Front 31

Felypressin (octapressin) chemical characteristics

Back 31

Is a synthetic analogue of the antidiuratic hormone vasopressin
It acts as a direct stimulant of vascular smooth muscle. Its action appears to be more pronounced on the venous microcirculation.
No direct effects on the myocardium

Front 32

What factors must be considered in selecting a vasoconstrictor

Back 32

the length of the dental procedure
the need for hemostasis during and following the procedure.
the requirement for post operative pain control
medical status of the patient

Front 33

Wht are some relative contraindications for epinephrine?

Back 33

Patients with more significant disease.
Patients with certain noncardiovascular diseases (such as thyroid dysfunction, diabetes, sulfite sensitivity).
Patients receiving MAO inhibitors, tricyclic antidepresants and phenothiazines.

Front 34

OraVerse (phentolamine mesylate)

Back 34

Indicated for the reversal of soft-tissue anesthesia and the functional deficits resulting from an intraoral submucosal injection of a local anesthetic containing a vasoconstrictor
It is not recommended for use in children less than 6 years of age or weighing less than 15 Kg.

can either do infiltration or block injection. 1/2 cartiage is equal to 0.2 mg.

0.4 mg/ 1.7 ml soln per cartridge

Front 35

What are some warnings and precautions for oraverse

Back 35

MI, cerebrovascular spasm, and cerebrovasular occlusion have been reported to occur following the parenteral administration of phentolamine. The events occurred in association with marked hypotensive episodes producing shock-like states.

tachycardia, arrythmias may occr

Front 36

Mechanism of action for OraVerse

Back 36

Produces an alpha-adrenergic block of relatively short duration resulting in vasodilation when applied to vascular smooth muscle

Front 37

What may occur with epinephrine towards the latter end of the dental procedure?

Back 37

The concentration will decrease and the beta affects (vasodilation) will dominate over alpha affects (vasoconstriction). This leads to increase post operative blood loss and may compromise a patient's cardiovascular status.

Front 38

What is an advantage with phenylephrine over epinephrine in terms of application during the dental procedure?

Back 38

Phenylephrine does not have any beta effects and is a pure vasoconstrictor. This is longer acting than epinephrine. However, it is a weaker vasoconstrictor than epinephrine so even though it has a longer duration, hemostasis during the procedure isn't as effective. but post operative bleeding passes with less bleeding.

We must note that phenyephrine is not included with any dental cartridge.

Front 39

What vasoconstrictor constricts venous circulation more than arterial circulation?

Back 39

Felypressin. It is of minimal value for hemostasis during a procedure and is not in dental cartridges.