Anaesthesia Flashcards
What are the types of anaesthetic medication?
- sedatives/tranquilisers
- analgesics
- anticholinergics
What animals do sedatives/tranquilisers commonly apply for?
Rodents but commonly used in larger speceis
What is the effect of sedatives?
Drowsiness with sluggish arousal response
What is the effect of tranquilisers?
Some relaxation and drowsiness but with rapid arousal response
Give some examples of sedative/tranquilisers.
phenothiazines
alpha-2 agonists
benzodiazepines
butyrophenones
What are the properties of phenothiazine and what are some examples of phenothiazine?
- Light sedation only
- Can be used in many species, but not in rodents
- Best not used in very old/young
- No analgesic properties - no pain release effect
- acepromazine -‘ACP’
wha are the properties of ACP?
-effective, inexpensive drug, capable of reducing induction and maintenance needs significantly.
-In fit and healthy animals of all species, ACP is a very useful and safe drug, producing light sedation.
-it should be avoided in very young animals (<12 weeks in cats/dogs) and used with care in geriatric animals.
-it has no analgesic properties of its own
-Potential adverse effects of ACP include hypotension and peripheral vasodilation
What are the properties of Alpha2 adrenoreceptor agonists and what are some examples of Alpha2 adrenoreceptor agonists?
- xylazine and medetomidine
- Commonly used in many species
- Very powerful sedatives
- Also some analgesic properties
What are the properties of Medetomidine?
-it produces stress reduction, dose related analgesia, muscle relaxation, good maintenance of core body temperature, stable anaesthesia, freedom from respiratory depression and is anti-arrhythmic.
-High doses of medetomidine can produce pronounced peripheral vasoconstriction (animal extremities become very pale), marked hypertension (blood pressure rises) and bradycardia (slow heart rate).
-When used in combination with an opioid, such as butorphanol or buprenorphine, the potential for unwanted side effects is quite low
What are the properties of Xylazine?
-It is the sedative of choice for cattle, and also works well in horses, but in most other species does not have any significant advantages over medetomidine.
-it is frequently used in combination with ketamine in the rodent species to
provide light surgical anaesthesia.
What are the properties of Benzodiazepines and what are some examples of Benzodiazepines?
- midazolam* – ‘Hypnovel’
diazepam** – ‘Valium’
[Controlled drugs * Schedule 3, **Schedule 4] - Typical tranquilisers
- Provide good “sedation” in rodents, rabbits, pigs and sheep
- Very good for old and young animals
- Less anaesthetic sparing effect compared with true sedatives - need to give higher concentration than normal sedatives
- usually in combination with an opioid, as this combination has minimal effects on the cardiovascular and respiratory systems.
What are the properties of Butyrophenones and what are some examples of Butyrophenones?
Examples: azaperone – ‘Stresnil’
* fluanisone – component of ‘Hypnorm’
* Limited use in veterinary practice
* Produces mild sedation with some anaesthetic sparing effect
* Used as a sedative in pigs
* Combined with fentanyl in ‘Hypnorm’ (widely used neuroleptanaesthetic mixture)
What is analgesics?
- Analgesia is the temporary abolition or diminution of pain perception.
- Analgesics are more effective when given pre- operatively (i.e. BEFORE experiencing painful stimuli)
- Some analgesics may cause mild sedation
- Analgesics can also reduce the total amount of anaesthetic required.
The types of analgesia?
a) Opioids
a) Non Steroidal Anti-Inflammatory Drugs (NSAIDs)
a) Local anaesthetics
What are the properties of opioids?
-Nearly all opioids are controlled drugs (strict recording & storage rules)
-Classically used to control SEVERE pain.
-Different drugs have different effects at different receptors.
-Many side effects – especially respiratory depression. Most opioids are short acting.
-Antagonists are often available.