DM1 P7-7 Adjunctive Analgesic Drugs Flashcards
Why might adjunctive analgesics be required in cats?
Adjunctive analgesics may be needed for cats undergoing invasive surgery or with altered pain states, like chronic pain.
How does ketamine provide analgesia?
Ketamine is an NMDA receptor antagonist, effective in reducing pain once central sensitization has developed.
When is ketamine used for pain management in cats?
Ketamine is used in low doses (sub-anesthetic) by continuous rate infusion (CRI) as an adjunct to opioid-mediated analgesia.
How do Alpha-2 agonists contribute to pain management in cats?
Alpha-2 agonists (e.g. medetomidine, dexmedetomidine) provide analgesia, sedation, and anxiolysis when given by continuous rate infusion (CRI).
What is a key side effect of Alpha-2 agonists?
Alpha-2 agonists can cause cardiovascular side effects and significantly increase urine production.
What are local anesthetics used for in pain management?
Local anesthetics (e.g. bupivicaine, lidocaine) provide analgesia via topical, infiltration, nerve blocks, epidural, or cavity administration.
What is the purpose of an epidural with local anesthetic?
Epidural injection of local anesthetic provides caudal abdominal, perineal, and hind limb analgesia.
What are wound catheters used for in pain management?
Wound catheters allow local anesthetic to be infused directly into a wound for long-term analgesia through repeated dosing.
How are regional nerve blocks used in cats?
Regional nerve blocks, like brachial plexus blocks, desensitize a large area of tissue, such as the forelimb distal to the elbow.
How is topical local anesthetic applied for pain relief?
Topical anesthetics like EMLA cream are applied to desensitize the skin for procedures like intravenous catheterization or blood sampling.
How do local anaesthetic drugs block pain sensation?
Local anaesthetic drugs block sodium (Na+) channels in nerves, preventing action potential propagation in sensory nerve fibres.
What is a common motor side effect of local anaesthetic use?
Local anaesthetics often block motor nerves, which can reduce mobility during the drug’s duration of action.
Which local anaesthetic drugs are most commonly used in cats?
Lidocaine and bupivicaine are the most commonly used local anaesthetics in cats.
What is the onset and duration of lidocaine?
Lidocaine has a quick onset (2-5 minutes) but a short duration of action.
What is the onset and duration of bupivicaine?
Bupivicaine has a longer onset (15-20 minutes) but a longer duration of action (6-8 hours).
What is EMLA cream used for in cats?
EMLA cream is used to desensitize the skin before procedures like intravenous catheterization or blood sampling.
What are the side effects of local anaesthetic overdose?
Overdose can cause CNS toxicity (dullness, seizures) and cardiovascular toxicity (bradycardia, hypotension, cardiac arrest).
What cardiovascular side effects are associated with bupivicaine?
Bupivicaine can cause hypotension, bradycardia, and even cardiac arrest at higher doses.
How can local anaesthetic injections cause pain?
Local anaesthetics are weak acids, which can cause pain on injection, especially in the post-operative period.
Why should local anaesthetics containing adrenaline not be used on end arterial sites?
Adrenaline causes vasoconstriction, which can lead to tissue ischemia in areas with limited collateral blood supply.
How is the larynx desensitized for intubation in cats?
A veterinary-licensed spray (e.g. Intubeaze) or 0.1-0.2 mL of 1% lidocaine can be used to desensitize the larynx.
What is EMLA cream used for?
EMLA cream is used to desensitize the skin before procedures like intravenous catheterization or blood sampling.
How is infiltration of local anaesthetic used in surgery?
Local anaesthetic is infiltrated around the incision line or a mass before skin closure or excision.
What are some examples of specific nerve blocks in cats?
Maxillary, mandibular, intercostal, and digital nerve blocks are used for localized analgesia, such as for dental procedures or chest wall desensitization.
