Local Anaesthetics in dentistry Flashcards
What does analgesia ?
The reduction or elimination of pain in a conscious patient
What do local anaesthetics do?
They eliminate sensations, especially pain, in one part of the body by the topical application or regional injection of a drug
Are local anaesthetics reversible?
YES they are reversible lockings of nerve conduction
What do local anaesthetics block?
They block entry of sodium ions into cells
What are the 3 types of local anaesthetics?
- Ester based – largely superseded (Procaine)
- Amino-amides
- Articaine
Give some examples of amino amide local anaesthetics
(lidocaine, Mepivocaine, Prilocaine, Bupivocaine
What is the most common local anaesthetic we administer and what is the dosage we give?
Lidocaine 2% plain or with epinephrine 1:80,000
Describe the effect of Mepivacaine 3% plain 2% with epinephrine
It is plain and very short acting
How are local anaesthetics metabolised excreted?
- Amino amides are metabolised by the liver
2. Excreted via the kidneys
What advise do manufacturers say about the use of lidocaine?
manufacturers advise caution in patients with liver disease
Who should we avoid giving Felypressin?
Avoid in pregnancy
Who should we taken caution in giving Adrenalin / Epinephrine?
Care in ischaemic heart disease, hypertensives, unstable angina
What do Vasoconstrictors increase in local anaesthetics?
Vasoconstrictors increase duration and depth of anaesthesia and reduce local blood flow
How can the operator reduce the chances of getting a needle stick injury?
Do not re-sheath or re-use
Use safety-plus system
What are some reasons local anaesthetic might fail?
- Insufficient solution injected
- Inaccurate placement
- Intravascular injection
- Biological variation
- Anatomical variation
- Some teeth more difficult than others (lower laterals)
- Infection or inflammation
How can patients have an allergy local cal anaesthetics?
Usually due to preservative
Was more common to ester-type (benzocaine, cocaine procaine)
What are some symptoms of local anaesthetic allergy?
- Swelling
- Nausea malaise
- May lose consciousness
- Facial and laryngeal oedema
What are Psychogenic reactions a patient could have to LA?
Feeling faint
Fainting
Palpitations
Panic attack
What is a Vasovagal attack?
Fainting
What should you do if your patient faints?
- Lie them flat - head down
- Loosen tight clothing
- Call for help
- Give them a Glucose drink
- Check – airway, breathing, circulation
- Oxygen if necessary
- If not recovered in 2-3 minutes – assume not simple faint
What can adrenaline interact?
Interacts with antidepressants MAOIs (possibly tricyclics)
Who should we take care with when administrating adrenaline?
Care in hypertension and heart problems (especially if unstable)
What some adverse events that can occur when administering LA?
- Broken needle (Rare)
- Pain during or after
- Haematoma
- Trismus
- IV injection
- Blanching
- Facial paralysis
- Prolonged impaired sensation
- Soft tissue trauma
- Visual disturbances
How can we make LA less painful?
- Use topical properly
- Room temperature cartridges
- Careful needle placement
- SLOW injection
- Do NOT retract tissues with a mirror.
How can we Maximise LA effectiveness?
- Good Communication skills
- Surface anaesthetics
- Good technique
- Solution at room temperature
- Patient comfort
- Stretch tissues
- Careful puncture
- Slow injection
- Explain sensation
What symptoms can patients have is they get LA toxicity?
Light headedness, sedation paraesthesia twitching Convulsions loss of consciousness, respiratory depression cardiovascular collapse
How much LA is usually found in 1 cartridge?
2.2ml
What is the maximum dose of lidocaine 2% we can give a health adult?
- 4mg/kg max 300mg
7x2. 2ml cartridges
What is the maximum dose of 3% Prilocaine we can give a health adult?
6mg/kg max 400mg
6cartridges
What is the maximum dose of 4% Prilocaine we can give a health adult?
6mg/kg max 400mg (4.5cartridges)
What is the maximum dose of 4% Articaine
we can give a health adult?
7mg/kg max 440mg (5cartridges)
What is the maximum dose of 2% Mepivacaine
we can give a health adult?
4.4mg/kg max 300mg (6.8 cartridges)
What is the maximum dose of 3% Mepivacaine
we can give a health adult?
4.4mg/kg max 300mg (4.5 cartridges)
What is the maximum dose of lidocaine 2% we can give a child?
2 2.2ml cartridges
What is the maximum dose of 3% Prilocaine we can give a child?
1.8 cartridges
What is the maximum dose of 4% Prilocaine we can give a child?
1.4 cartridge
What is the maximum dose of 4% Articaine we can give a child?
1.5 cartridges
What is the maximum dose of 2% Mepivacaine we can give a child?
2 cartridges
What is the maximum dose of 3% Mepivacaine we can give a child?
1.4 cartridges
What should we beware of with the elderly?
Over the age of 65 liver function in the elderly reduces by 60%
Therefore reduce safe dosages by 50%