Intro and Pharmacology Flashcards
Define analgesia.
The loss of pain sensation.
What is local anaesthesia?
A method of anaesthesia which acts in a specific area and does not result in a loss of conciousness.
Topical is the anaesthesia of surface tissues, what procedures is it used for in dentistry?
- Pain free injections
- Very minor oral surgery (biopsy)
- Abscess incision
- Palate for taking impressions on people with strong gag reflex
What is the main factor which limits the effectiveness of an infiltration injection?
The permeability of the tissues through which the anaesthetic has to pass.
What makes anaesthetising the upper molars by infiltration difficult?
They are surrounded by thicker bone.
What is a regional block injection?
Anaesthesia achieved by blocking a nerve trunk at some distance from the site of operation. Eg. Inferior alveolar nerve block
What is the UK trade name for mepivacaine?
Scandonest
What is the drug name of septanest?
Articaine with adrenaline
What component of the anaesthetic usually causes allergic reactions?
The preservative which is added when there is a vasoconstrictor.
Which anaesthetic drug is the longest lasting and is it an ester or an amide?
Bupivicaine
Amide
What makes articaine different in structure to other drugs and what does this factor do to the rate in which it is broken down?
It has both an amide and an ester link, this causes it to be broken down more readily.
If a drug has a low pH what does this tell you about the onset?
It will be slow onset.
What effect does the protein binding ability of the drug have on it’s action?
It prolongs the duration of the drug as binding to protein there is a pool of the drug available.
Which type of nerve fibre is anaesthetised the quickest?
C fibres
Which nerve fibres are the first to regain activity after the administration of a local anaesthetic?
A alpha
What effect do local anaesthetics have on the myocardium?
Reduces the excitability and conductivity.
What is the initial effect of local anaesthetics on the CNS?
Stimulation
What type of drug is primarily broken down in the plasma?
Articaine
Why are vasoconstrictors added to local anaesthetics?
- increase speed of onset
- counteract their vasodilatory effect
- extend duration
- lower blood levels of LA
- reduces haemorrhage
What are the two types of vasoconstrictors added?
Sympathomemetic amines and synthetic polypeptides (e.g. Felypressin)
What does of adrenaline would you expect in a cartridge of local?
1:80000
What makes felypressin not effective at causing haemostasis?
It works on the venous side
When should you reduce the dose given to a patient?
Liver disease On beta blockers Calcium channel blocker Drug abuse Tricyclics anti-depressants Mono-amine oxidase inhibitors
Define anaesthesia.
The loss of all sensation.
