Local Anaesthesia Pharmacology Flashcards
(24 cards)
contents of LA?
LA agent vasoconstrictor reducing agent fungicide preservative carrier solution
purpose of vasoconstrictor?
prolongs anaesthetic time
purpose of reducing agent?
prevents oxidation of vasoconstrictor
competes with adrenaline for O2
purpose of preservative?
without, shelf life = 18months to 2 years
can provoke an allergic reaction
example of a fungicide?
thymol
purpose of carrier solution?
modified ringers lactate solution , adjusted for biocompatible pH
details of lidocaine?
2% solution dissolved in hydrochloride salt in topical pastes on its own - no lasting pulpal anaesthesia \+ epinephrine 1:80 000
prilocaine?
3% with octapressin
4% plain
prilocaine with octapressin sim to lidocaine with epinephrine
less effective at controlling haemorrhage, only slight vasoconstrictive properties
mepivicaine?
2% 1:100000 epinephrine sim to lido/ep
3% plain sim to prilocaine plain
articaine?
4% 1:100000/1:200000 epinephrine
sim to lido and ep
more quickly metabolised
useful for repeat injections
epinephrine?
more profound anaesthesia
longer lasting
haemostasis
felypressin?
sim to vasopressin
conc 0.03iu/ml
not as effective at haemorrhage as ep
what kind of toxicity can occur?
intravascular
systemic distribution of relatively high doses of anaesthetic and vasoconstrictor
sufficient LA in a cartridge to give toxic levels of agent in CNS of children and small adults
what LA for a pt with a latex allergy?
citanest
pt’s with liver disease be wary of?
high risk of toxicity because of impaired metabolism
what can impact on cardiac disease?
use of epinephrine
if a pt has cardiac disease give what?
felypressin - max 3 cartridges
problems with pregnant pt’s and la?
felypressin mimics oxytocin - effect on uterus
100 cartidges - induce labour
max doses for av. 70kg pt?
lidocaine 2% plain - 11
lidocaine 2% 1:80 000 - 6.8
prilocaine - 3% octapressin 0.03iu/ml = 9
prilocaine 4% plain =4
limit dose of analgesic with?
beta blocker = 2 cartridges with ep
calcium channel blockers
limit dose of vasoconstrictor with?
beta blockers, diuretics, ca channel blockers, antiparkinson drugs
cocaine/cannabis in past 24 hours avoid?
epinephrine
medical contra indications to LA?
leukaemia, anticoagulant therapy
steroid therapy, liver dysfunction, renal disease, pregnancy,
rheumatic fever, uncontrolled diabetes, taxaemia, haemophilia
local complications to LA?
infection, haematoma, nerve damage, facial palsy