This document discusses local anesthetics and vasoconstrictors used in dental procedures. It describes how epinephrine acts as a vasoconstrictor to decrease blood flow and slow absorption of local anesthetics, prolonging their duration and depth. It provides details on the classification, mechanisms of action, effects on cardiovascular and other systems, maximum recommended doses, contraindications, and alternatives to epinephrine for patients with certain medical conditions.

1. Based on Text- Local Anesthesia for Dental Professionals
1st ed. Dr. StanleyMalamed 2nd ed. Bassett, DiMarco,
Naughton
Local Anesthesia for Dental Professionals

3.  LA are vasodilators
 Dilation results in
 Increased rate of absorption of LA into CV system
 Removes drug
 Higher plasma levels of LA
 Increased risk of toxicity
 Decrease in depth and duration of LA
 Diffusion away from site and redistribution
 Increased bleeding at site of treatment

5.  Decrease blood flow – perfusion to site
 Slows absorption of LA into CV system
 Blood levels of LA are lowered
 Increase in LA concentration gradient into nerve
 Decreased bleeding at site of administration

6.  Chemically identical or similar to
 Sympathetic nervous system mediators
(neurotransmitters)
 Epinephrine & Norepinephrine
 Classification
 Sympathomimetic or Adrenergic

8.  Chemical structure related to catechol nucleus
 If an amine group is attached to aliphatic side
 Classified as catecholeamine
 Naturally occurring Catecholamines
 of Sympathetic System
 Epinephrine
 Norepinephrine
 Dopamine
 Synthetic Catecholamies
 Isoproterenol & levonordefrin

9. Catecholamines
 Epinephrine
 Norepinephrine
 Dopamine
 Levonordefrine
 Isoproterenol
 Amphetamine
 Methamphetamine
 Ephedrine
 Methentermine
 Hydroxyamphetamine
 Metaraminol
 Methoxamine
 Phenylephrine
Noncatecholamines

10.  Direct acting
 Act directly on adrenergic receptors
 Indirect acting
 Acts by releasing norepinephrine from adrenergic nerve
terminals
 Mixed acting
 Both directly on receptors and release of norepinephrine

11.  Found in most tissues of body
 Alpha and Beta receptors
 Inhibitory or excitatory

12.  Alpha receptors
 Activated by sympathomimetic drug
 Vasoconstriction
 Contraction of smooth muscle in blood vessel
 Alpha 1 excitatory postsynaptic
 Alpha 2 inhibitory postsynaptic

15.  Beta Receptors
 Beta 1 - Found in heart and intestines
 Cardiac stimulation and lipolysis
 Increased heart rate and strength of contraction
 Beta 2 - Found in bronchi, vascular beds, uterus
 Bronchodilation and vasodilation

16.  Amphetamine or tyramine
 Act indirectly
 Causes release of norepinephrine from storage in
nerve terminals
 Action is that of the released norepinephrine
 Repeated doses of drug is less effective due to
depletion of norepinephrine
 Called Tachyphylaxsis
 Only seen with indirect acting drugs

17.  Ratio of drug to carrier medium
 1:1000 = 1 g or 1000 mg of solute (drug)
 to 1000 mL of solution
 1:1000 contains 1000 mg in 1000 ml
 1:10,000 contains .1 mg/mL
 1:100,000 contains .01 mg/mL
1:100,000 xylo 2% w / epi - .01mg/ml x 1.8 ml = .018 mg epi

18.  Used to prolong the duration of LA
 1:200,000 epi contains .005mg/mL epi
 provides comparable results with fewer systemic side effects
 Widely used and accepted in dentistry and medicine

19.  Resting plasma level
 Doubled after administration
 of one carpule of 1:100,000 epi
 Epinephrine levels equivalent to moderate to heavy
exercise occur after intraoral injection
 Associated with moderate increases in cardiac output and
stroke volume
 Blood pressure and heart rate are minimally affected

20.  Sympathomimetic reactions
 Apprehension
 Tachycardia
 Sweating
 Heart palpitation

21.  Intravascular injection
 Hyperresponders
 Increase in heart rate of
25 – 70 beats per minute
 Elevation in BP 2 to 70
mm HG
 Rhythm disturbances
 Premature ventricular
contractions (PVC’s)

23. Alpha 1 stimulation by epinephrine

24.  Lacks significant beta 2 activity
 Produces intense peripheral vasoconstriction
 Possible DRAMATIC elevation in BP
 Side effect ratio
 9 times higher than epinephrine

25. Acts on Alpha and Beta receptors
with Beta dominating

26.  Myocardium
 Beta 1 receptors stimulated
 Positive inotropic – force of contraction
 Positive chronotropic - Cardiac output and rate
increased
 Pacemaker cells
 Beta 1- increased irritability of cells
 Increased dysrrythmias

27.  Coronary Arteries
 Dilation of CA and increased blood flow
 Blood Pressure
 Systolic BP increased
 Large doses – diastolic increased due to systemic
constriction
 Caused by alpha receptor response

28.  CV dynamics
 Direct stimulation
 Increased systolic and diastolic BP
 Increased Cardiac Output
 stroke volume & heart rate increased
 Increased strength of contraction
 Increased myocardial demand for oxygen

29.  Vasculature
 Constriction due to alpha receptor stimulation
 Skin, mucous membranes, kidneys
 beta 2 receptors
 dilation
 alpha 1 receptors
 constriction

30.  Hemostasis
 Epi is used for vasoconstriction
 Predominant alpha 1 receptor action
 Beta receptors domination
 Reverts to dilation and increased bleeding
 Post op bleeding 6 hours after injection
 Respiratory System
 Potent dilator due to Beta 2 stimulation
 Bronchiolar smooth muscle relaxed
 Management of bronchospasm – status asthmaticus

31.  CNS
 Not a potent CNS stimulant
 Metabolism
 Epi increases oxygen consumption in all tissues
 Beta stimulation – glycongenolysis in liver and skeletal
muscle
 Elevates blood sugar
 Termination of action
 Reuptake in adrenergic nerves
 Inactivated in
 blood by COMT - catechol-O-methyltransferase
 In Liver - Hepatic system by MAO - monoamine oxidase

34.  Maximum dose
 1:100,ooo concentration recommended in USA
 Typical concentrations of epi in LA are not
contraindicated
 Aspiration is mandatory
 Inject slowly
 Smallest effective dose administered
 Maximum dose limited to .2 mg per appointment
 .018 mg/cartridge
.2 mg epi / .o18 mg/ carpule = 11 carpules

35.  Overdose
 CNS stimulation
 Increasing fear, tension
and anxiety
 Tension, tremors,
weakness
 Dizziness, palor,
palpitation and
respiratory difficulty

36.  Cardiovascular compromised patient
 Limit or avoid vasoconstrictors
 ASA 3 - 4 poorly controlled are greater risk
 Weigh risk to benefit
 Hemostasis
 Infiltration into site
 Minimize hemorrhage due to vasoconstriction
 Rebound effect due to beta predominating

37.  Neo-Cobefrin
 Used with mepivicaine –
carbocaine
 Mode of action thru
 direct alpha 75%
 and beta stimulation
25%
 15% as potent as
epinephrine

38.  CV dynamics = epi
 Vasculature = epi
 Termination of action and elimination
 COMT
 MAO
 Maximum dose = 1 mg per appointment
 15% as effective as epi so a higher concentration is used
 1:20:000 = .09 mg/cartridge
1 mg / .09 mg/carpule = 11 carpules

39.  Epinephrine - or – Levonordefrin ???
 Length of dental appointment
 Prolongs duration and depth of anesthesia
 Restorative for 50 minutes = may need epi or levo
 Requirement for hemostasis
 Vasoconstriction with rebound vasodilation
 Medical status of patient
 Risk / benefit must be evaluated

40.  Medical status of patient
 Risk / benefit must be evaluated
 ASA 3 – 4
 Thyroid disease
 Diabetes

41. Sulfite sensitivity
 Antioxidant to preserve
epi
 Acidifies the solution
increasing cations
 diffusion into axon is
slower
 Delayed onset of LA

43.  Trycyclic antidepressants
 Greater risk of dysrythmias
 Levonordefrin is contraindicated
 Norepinephrine is contraindicated
 Phenothiazines
 With epi may cause postural hypotension
 Non-selective beta blockers
 Beta blocked and alpha dominates
 Peripheral constriction (HTN ) and bradycardia

44.  Unstable diabetes
 Epi causes glycogenolysis
 hyperglycemia and ketoacidosis
 Unstable – active angina
 Epi stimulates beta receptors
 increasing cardiac rate and oxygen demand
 Recent MI / CABG
 Medical consult prior to care

45.  Severe HTN or untreated HTN
 Contraindicated if uncontrolled (over 170 systolic)
 Uncontrolled CHF
 The pump is simply failing and patient is a poor risk

46.  Slows rate of absorption
 Lowers systemic blood levels of LA
 Prolongs duration of LA
 Intensifies depth of LA
 Reduces systemic reactions