MOD 20 - COURSE 2 - PT 2 - INJECTABLE Flashcards
the drug concentration in the blood doesnt correlate to…
anaesthetic depth based on subjective observations -
- can be differnet by differnet methodsof injection
(SC,IV,IM,IP)
why does dose of anaesethic need to vary ebtween species
- anesthetic uptake, distribution, effect = givenered by pharmocokinetic adn dynamic proprtiers of anaesethic agent in that strain or species
- individual variation = also plays important role in biodisposition and pharamcokinestics as well as therapeutics
- variation includes - genotypes, stock strain, sex, age, body compositions, nutritional and disease statys
what are the most common injectables used in the lab for anaesethics
- barbituates
- pentobarbital
- thipental
- methohexital
- coral hydrate
- xylazine/medetomidine
- ## phenothiazines and butirophenones
what is the effects of barbituates
- effects - persisit several hours even with short acting barbituates
- readily absorbed from most sites i.e. GI tract - however - highly alkaline - so limited for IV administration
- considered good hypnotic agents but poot anaglesics
what is the effects of pentobarbital
- severe cardiovascular resp system depression - poor anaglesic acitivyt
- causes pain if IP due to high Ph
What are the effects of thiopental
- short acting barbiturate -useful - rapid induction of anaesethesia when administed intravenously - cause transient apnea
- irritant if injected perivascularly - diluted as much as practicable
what are the effects of methohexital
- poor anaglesic acitivty - transient apnea ofent occurs
- muscle tremour during recovery unless suitable preanaesthetic medication = administred
what is transient apnea
- breathing problems
what is the effects of coral hydrate
- achieve medium - duration, light anaesthesia - minimal efect on cardiovascular function or relfexes
- poor anaglesic acitivty
- need high dose for surgey - can have severe repiraoty issue - not recommeneded
what are the ffects of medetomidine / xylazine
used alone - sedative/anaglesic agent
- combined with other anaesthetic agents
- administed as constant rate at low doses for anxiolysis/analesia
- most effective if combined with opiods or dissociative anaesthetics i.e. ketamine
- are antagonist drugs - reverese the effect : tohimbine and atipamezole
what antagonsits are there for xylazine and medetomidine
yohimbine and atipamezol
what are the effects of phenothiazianes and butirophenones
- sedation - dont produce sleep, anaglesia or ananethesia even in increased dose - they causes decreased spontanous movement and complex behaviours , pscyhomotoe agitation, curiosity and apparent aggressiveness = reduced
- use ajunct with other anaestehtic i.e. opiods and ket
what are some examples of phenothiazines
- chlorpromazine, promazine, acepromazine
what are some exampels of butirophenones
- droperidol
- fluanisone
what are some effects of benzodiazepines
- not true general anesethic state - awareness and relxation = not sufficnet for surgery
- not compatible alone to genral anaesetheitc- uses of preanaesethsia and anaesethsia induction
- used for their sedative, anxiolytic, relaxation and anticonvulsant activity
wxamples of benzodiazepines
- diazepam, midazolam, zolasepam - (typically incombination with other agent i.e hypnotic or dissociative - for anaesthesia or anaesethic induction)
how can you improve the quality of anaesethesia given to the aniamsl
- combination of 2+ drugs - balanced - improve saftey reduce dose adn corresponding side effect for each compoenent
what are the 2 types of combinations most widely used for anaesetheis
- neuroleptoanaglesia
ketamine combination
what is neuroleptoanaglesia
- combination of opiod anaglesic (fentanyl) and a tranq
what are some examples of transquilisers - used for neuroleptoanalgesia
- can be a dopaminergic receptor antagonist : fluanisone, droperidol, acepromazine
- or a benzodiazepine : midazolam and diazepam
how can the effect of the combination be revered for neuroleptoanalgesia
- by admin or mu-opiod antagonist i.e. naloxone, nalbuphine or butorphal
what is a ketamine combinations and what is its goal
- improved anaglesia, muscle relax, sedation, prolonged duration, decrease side efects
- mix ket toether with other anaesethic drugs to offset their side effects
what are 2 common ketamine combinations
- ketamine and xylazine
- ketamine and diazepam
whatelse can be used with ketamine to get the same effects as whe using ketamine mixed with xylazine
medetomidine
