Week Four: Local Anaesthetic Types Flashcards

1
Q

What is intrinsic anaesthetic potency?

A

Concentration and lipid solubility

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2
Q

What is ‘onset of anaesthesia?’

A

Dependant on speed agent passes through the tissue, proximity to the injection site to target nerve and diameter of nerve fibres

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3
Q

What is ‘duration of action’?

A

Dependant on rate of diffusion away from target site, related to protein binding affinity & presence absence of a vasoconstrictor

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4
Q

What is ‘effects on other tissues?’

A

Effects excitable tissues. Could see toxic affects on the cardiovascular system and nervous system.

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5
Q

What is ‘Rate of degradation and elimination?’

A
  • Amides broken down in the liver, significant liver disease and other drugs may effect the rate it is broken down, and subsequently how long it takes to be removed from the body.
  • Significant kidney disease may also impact this.
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6
Q

Concerns with LA and pregnancy?

A

LA can cross the placental barrier.

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7
Q

Topical Anaesthetics: What is available?

A

Various agents are available today for topical analgesia.

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8
Q

Topical Anaesthetics. General onset time and duration?

A

Onset time: 2-5 minutes

Duration: 15-20minutes

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9
Q

General indications of topical anaesthetics?

A
  • Anaesthetise mucous membranes

- Surface anaesthesia of gingiva prior to injections

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10
Q

Contraindications of topical anaesthetic?

A

Known allergy

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11
Q

Precautions of Topical?

A

Overdose, eating or drinking.

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12
Q

What are some examples of topical anaesthetics?

A

Xylocaine® 10% special adhesive
- Active ingredient: lignocaine

Xylocaine®5% ointment
◦ Active ingredient: lignocaine

Xylocaine® spray

Num ®
◦ Active ingredient: benzocaine

Oroqix ® (periodontal gel)
◦ Active ingredient: lignocaine and 2.5%/2.5%
◦ Periodontal Gel is supplied in dental cartridges that provide 1.7 g gel.
◦ For use on adults
◦ Thermosetting abilities, thus retained in pockets

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13
Q

What are the six basic components of local anaesthetic?

A
  1. Anaesthetic Agent (weak organic base- insoluble in water)
  2. Stabilisers- salts (converts agent so it is water soluble)
    ◦ Usually the hydrochlorides
  3. Vasoconstrictors (increase duration of action of L.A)
  4. Antioxidants (prevents oxidation of stabiliser)
    ◦ Sodium metabisulphite
  5. Preservatives
    • Fungicides, antibacterials
    • Methylparaben
  6. Water
    ◦ Distilled water, increases volume of solution
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14
Q

Vasoconstrictors are added to local anaesthetics for?

A
  • Longer lasting L.A
  • More profound L.A
  • Reduced operative haemorrhage
  • Reduced systemic effects
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15
Q

What type of vasoconstrictors are used in dentistry usually?

A
  • Sympathomimetics (adrenaline) or

* Synthetic polypeptides (octapressin/felypressin)

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16
Q

What is adrenaline?

A

Naturally occurs in the body
Binds to adrenoreceptors and exerts its effect on a number of body
systems
Sympathomimetic

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17
Q

What is the action of adrenaline in the heart?

A

• Acts on β1 receptors increases HR and contractility thereby
increasing CO, acts on β2 for coronary artery dilation
• Increase CO, increased BP

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18
Q

What is the action of adrenalin on blood vessels?

A

• Produces vasoconstriction by acting on the on blood vessels
• α 1 and α2 produce constriction of skin and mucous membranes, β2
results in skeletal muscle vasodilation

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19
Q

What is the effect of adrenaline on the lungs?

A

It acts on B2 receptors and leads to bronchiolar muscle relaxation.

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20
Q

What is the effect of adrenaline on the GI tract?

A

It reduces gut contractility, decreases saliva flow.

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21
Q

What is the effect of adrenaline on metabolism?

A

It can inhibit insulin release and lead to slightly elevated levels of circulating glucose.

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22
Q

What does Felypressin do?

A

Felypressin causes vasoconstriction by acting on smooth muscle of the vascular beds, with greater effects on the venous side of the peripheral circulation.

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23
Q

Why is Felypressin indicated for some patients.

A

Felypressin is appropriate for patients when adrenaline is contraindicated.

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24
Q

Name ‘amide’ type local anaesthetics.

A
Lidocaine/Lignocaine
Articaine
Prilocaine
Mepivacaine
Bupivacaine
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25
Q

What are the pharmacological properties of lidocaine/lignocaine?

A

Highly lipophilic therefore rapidly adsorbed and short onset of action

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26
Q

What is the metabolism of lidocaine/lignocaine?

A

(95%) Hepatic

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27
Q

What is the elimination half life of lidocain/lignocaine?

A

90-120minutes

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28
Q

What is the onset of action for lidocaine/lignocaine?

A

2-3minutes

29
Q

What is the duration of action for lidocaine/lignocaine?

A

60-90minutes to the pulp
60-120 minutes for soft tissues.
with vasoconstrictor

30
Q

Lidocaine/lignocaine is?

A

The most commonly used dental LA.
Proprietary names are also known as:
- Xylocaine (2%lignocaine with 1:80 000 adrenaline) - Topical agent.

  • Lignospan. - Anaesthetic cartridge
31
Q

What is the max dosage of lidocaine/lignocaine?

A

7mg/kg absolute max. (500mg adult) for 2%lignocaine with 1:80 000 adrenaline Xylocaine.

32
Q

What is the metabolism of Prilocaine?

A

Metabolism is by product of metabolism (methaemoglobin) can exert effects on tissues in large doses.

33
Q

What is the elimination of half life for prilocaine?

A

It has the highest clearance of all amide-rapid metabolism in the liver. It accounts for this additional clearance in the lungs and kidneys.

34
Q

What is the duration of action for prilocaine?

A

40-90 minutes in the pulp
150-210 minutes for soft tissues. ;
with felypressin

35
Q

What are some pharmacological properties of prilocaine?

A
  • Slightly slower onset than lignocaine
  • Less vasodilatory, distributed more rapidly, larger volume of distribution.

Used as an alternative preparation when adrenaline precaution/contraindication.

36
Q

Preparations and proprietary names of prilocaine?

A

3% Prilocaine HCl with felypressin (0.03 IU/mL) Citanest ® with octapressin
• 4% Prilocaine HCl only Citanest ®15
• 3% Prilocaine HCl with adrenaline (1:300,000) Citanest ® 30 with adrenaline

37
Q

What is the maximum dosage for prilocaine?

A

Maximum recommended dosage 9.0mg/kg, Absolute max
(600mg adult) 3% Prilocaine HCl with Felypressin (0.03 IU/mL) Citanest ®
with octapressin

38
Q

What is the metabolism of Articaine?

A

Unlike the other amides, articaine undergoes some biotransformation in the blood plasma in addition to the liver.

39
Q

What is the elimination half life of articaine?

A

approximately 20minutes

40
Q

What is the onset of action for articaine?

A

2 minutes

41
Q

What is the duration of action for Articaine?

A

60-75 minutes for the pulp

180- 360 minutes for the soft tissues.

42
Q

What category drug is articaine?

A

Category C

43
Q

What are the preparations and Proprietary names for articaine?

A

–4% Articaine HCl 1: 100 000 adrenaline
Septanest 1: 100 000
–4% Articaine HCl 1: 200 000 adrenaline
Septanest 1: 200 000

44
Q

What is the maximum dosage for articaine?

A

Maximum recommended dosage 7mg/kg absolute max
(500mg adult) of 4% Articaine HCl 1: 100 000 adrenaline
Septanest 1: 100 000

45
Q

What type of metabolism does Mepivacaine use?

A

Hepatic

46
Q

What is the elimination half life of mepivacine?

A

114-192 minutes

47
Q

What is the onset of action for mepivicaine?

A

1.5-2minutes

48
Q

What is the duration of action for mepivacaine?

A

20-40minutes for the pulp

120-180 minutes for soft tissues

49
Q

What category drug is Mepivacaine?

A

Category C

50
Q

What are the pharmacological properties of Mepivacaine?

A

It is the least vasodilatory of all the amides
It is similar to lignocaine, but shorter duration of action
It used when you need a vasoconstrictor free solution
It also has an incredibly low incidence of allergy

51
Q

What are the preparations and proprietary names for Mepivacaine?

A

• 3% Mepivacine Hydrochloride Scandonest Plain®
• 2% Mepivacine Hydrochloride with adrenaline
1:200 000 Scandonest Special ®

52
Q

What is the dosage requirements for mepivacaine?

A

• Not specified in Australian Product Information- TG recommends not to
exceed 3 cartridges of either

53
Q

What type of metabolism does bupivacaine have?

A

Hepatic

54
Q

What is the duration of action for bupivacaine?

A

90-180 minutes into the pulp

240-540 minutes for soft tissue

55
Q

What category drug is bupivacaine?

A

Category C Drug

56
Q

What pharmacological properties does bupivacaine have?

A

Long lasting and high protein binding (this increases the duration of action)
It is used at low concentrations due to its cardiotoxic effects.

57
Q

What are the preparations and proprietary names for bupivacaine?

A

• 0.5% Bupivacaine HCl with adrenaline (1:200,000)

Marcaine ® with adrenaline

58
Q

What are the dosage guidelines for bupivicaine?

A

• Maximum recommended dosage 1.3mg/kg absolute max (90mg adult)
No indication for the OHT to use this type of LA

59
Q

What type of conditions contraindicate local anaesthesia’s?

A
  • Hypersensitivity to any components
  • Serious IV conduction defects
  • Severe hypotension
  • Severe liver and renal disease
60
Q

What type of conditions where cartridges containing adrenaline are contraindicated?

A
  • Adrenal tumors
  • Uncontrolled hyperthyroidism/not on HRT
  • Uncontrolled diabetes/elevated blood glucose
  • Cardiovascular disease
    (Unstable angina, recent myocardial infarct and refractory cardiac dyshythmias, uncontrolled HBP - (>200mmHg systolic >115 mmHg diastolic))
61
Q

What conditions require precautions?

A
  • Impaired renal function and liver disease (dose reduction)
  • Cardiovascular disease (adrenaline dose reduction)
  • Atypical pseudocholinesterase (avoid Articane and esters)
  • Pregnancy (avoid category B3, C, D and X medications)
  • Coronary artery disease (Avoid high doses of felypressin)
62
Q

What conditions require precautions?

A
  • Children (dose reduction)
  • Elderly (dose reduction)
  • Certain medications
    Medications can interact with the drug, or may increase the risk of toxicity.
63
Q

Are there drug interactions with local anaesthetic?

A

Many drug interactions are theoretical or are
associated with higher doses of local
anaesthetic preparations than those used for
dental procedures in primary care
More associated with combined use of
adrenaline
• Exogenous drugs effect or compete with the
pathways responsible for the metabolism of
adrenaline in the body

64
Q

What drugs are there no/low evidence of interactions at current low doses used in dentistry?

A
  • Antibacterials (sulphinoamides)
  • Anti-arrhythmics
  • Anti-secretory agents
  • Anti virals
  • Anticonvulsants
65
Q

What drugs require precautions with LA?

A
  • Non selective beta blockers
  • Tricyclic Antidepressants and SNRIs and MAOI
  • Phenothiazines
  • CNS depressants, sedatives, opioids, halothanes
  • Drugs of abuse: Cocaine, inhalants and cannabis can exacerbate effects of adrenaline.
  • Diuretics
66
Q

If you are ever uncertain about anything regarding giving LA and a patients medication what should you do?

A

Check the therapeutic guidelines and avoid adrenaline containing solutions.

67
Q

What should you keep in mind when considering anaesthetic dosage?

A

• As discussed, CNS and CVS are very susceptible to
actions of L.A.
• Systemic actions are related to the blood or plasma
level of the L.A agent
• This is determined by amount injected and site of
injection
• Do not exceed maximum recommended doses,
otherwise patient may overdose
• Know amount of Local in preparation (2.2mls/1.8mls)

68
Q

How do you calculate the maximum recommended dose?

A
  1. Determine amount (in mg) of the local anesthetic present in the cartridge
    = Volume of cartridge (ml) x Concentration of active agent (mg/ml)
    (Calculate the mg/mL using the basic formula mg=% x 10 x ml)
  2. Identify maximum dose in mg/kg for a specific Local Anaesthetic
    (manufacturers recommendations) and multiply by pt’s weight
  3. Determine how many cartridges this is equivalent to:
    = maximum dose for the clients weight/ Amount in mg in
    cartridge