Flashcards in Pre-Medications Deck (66)
Why give pre-meds?
-Provide sedation and analgesia
- Calm the patient for smooth induction
- Reduce dose of induction and maintenance agents required
- May help reduce some adverse effects of the anaesthetic or surgical procedure
What is balanced anaesthesia?
- Using multiple drugs in combo to achieve anaesthesia
- Provide better quality of anaesthesia
- Minimise total doses of agents used whereby reducing potential side affects
- All tailored to the individual patient
- Balance out side effects with other drugs
What are the golden rules to using Pre-meds
- correct does tailored to the individual animal!
- Should be given and left in a quiet environment
- Give enough time for the drug to take effect
- note the route of admin (may impact time to reach effect and duration of effect)
How long do most pre-meds take to cause an effect?
What are Alpha-2-Agonists ?
Drugs that bind to alpha-2 receptors in the brain and spinal cord
How do Alpha-2-agonists work ?
Block transmission of nociceptive impulses
Exact mechanisms not fully understood
What do Alpha-2-Agonists provide?
Sedation and Analgesia
Name 2 Alpha-2-Agonists
What are Alpha-2-Agonists used for?
What other drug to Alpha-2-Agonists work with for sedation?
Opioids (usually buprenorphine)
What is a major benefit when using Alpha-2-Agonists as pre-medication
Can achieve a profound sparing effect which lowers the doses of other agents required for induction and maintenance
What other drug is commonly used with Alpha-2-Agonists for anaesthesia
Ketamine - especially in cats
What analgesic approach can Alpha-2 Agonists be used as a part of
multi-modal analgesic approach
Name 4 potential side effects with Alpha-2-Agonists
- Causes vasoconstriction
- Can cause profound bradycardia
- Causes respiratory depression
- Reduces liver blood flow
- May cause vomiting
What patients should you not use Alpha-2-Agonists on or have extreme caution in using on
- Patients with cardiovascular disease
- Patients with liver disease
- Patients where vomiting would be risky
Name 4 advantages of Alpha-2-Agonists
- There is a reversal drug (Atipamezole)
- Profound drug sparing effect
- Provides muscle relaxation
- Provides Analgesia
- Duration and level of sedation are dose dependent
What are opioids?
Light sedative effects
How do opioids work?
Act by combining with specific receptors in the brain and spinal cord (OP3 most commonly) and decrease the transmission of noxious stimuli
What are the three kinds of Opioids?
How do full agonist opioids work and when would you use it?
Produce maximal effect and bind all receptors
Used for moderate to severe pain e.g. bitch spay
Give an example of a full agonist opioid
Morphine, methadone, pethidine, fentanyl
What other drugs are used in combo with partial agonist opioids
Alpha-2's or phenothiazine
What form of pain is a partial agonist opioid use in and give an example of a partial agonist
Mild to moderate pain
What is the function of an antagonist opioid?
Work against the analgesic effects of the agonist - can be used as an antidote
Give an example of an antagonist and where it is commonly found
Often found in emergency crash kits
What kind of Pre-meds are opioids usually combined with
Name 2 schedule 2 opioids
Name 2 schedule 3 opioids
Benefits of using an opioid?
- provide analgesia and euphoria, sedation
- Little effect on respiration at correct dose
- Drug sparing effect
- Little effect on CVS but can cause bradycardia
- Pain relief provided may improve ventilation in cases of thoracic wall injury