Analgesic Agents: non-opioids Flashcards
(47 cards)
At what point along the neural pathway do NSAIDs target?
- At the Nocicepter itself: working locally to reduce the inflammatory ‘soup’, and thus reduce the speed of TRANSDUCTION and magnitude
- At the spinal cord: to alter MODULATION
At what point along the neural pathway do Local anesthetics target?
- At the Nocicepter itself: working locally to reduce the inflammatory ‘soup’, and thus reduce the speed of TRANSDUCTION and magnitude
- At the peripheral nerves: thus reducing TRANSMISSION of signals
- At the spinal cord: to alter MODULATION
At what point along the neural pathway do NMDA antagonists target?
- At the spinal cord: to alter MODULATION
At what point along the neural pathway do alpha1 agonists target?
- At the peripheral nerves: thus reducing TRANSMISSION of signals
- At the spinal cord: to alter MODULATION
- At the brain: to alter PERCEPTION and promote the descending inhibitory pathways of pain
What are the roles of PGE2, PGF2 and PGD2?
- Pro-inflammatory: tissue edema, swelling and redness
- Increase perception of pain
- Induce Fever
What are the roles of PGI2?
- Inhibition of coagulation
- Decrease platelet aggregation
What are the roles of Thromboxanes?
- Stimulate coagulation
- Increase platelet aggregation
What are the roles of COX1 and COX2?
COX1: produce substances important for normal homeostasis. Turn AA into Thromboxanes
COX2: produces inflammatory mediators. Turn AA into PGI2 and PGE2
Where in the body are NSAIDs metabolized and excreted?
Metabolized: Liver, via glucuronidation
Excretion: Urine
The duration of action of NSAIDs is dependent on the ability of glucoronidation in the liver, which species have a better and which species have a limited ability to undergo glucuronidation?
Better: Donkeys- therefore require more frequent dosing
Limited: Cats- therefore toxicity is more likely
What are the main effects of NSAIDs?
- Anti-inflammatory (locally)
- Analgesic (local and systemic)
- Antipyretic
- Anti-endotoxic
- Anti-thrombotic
- Anti-spasmodic
What are the side effects associated with NSAIDs?
- Vomiting, diarrhea
- Anorexia
- Abdominal pain
- GI ulceration
- Predispose kidneys to injury by inhibiting PG, and thus vasodilation cannot occur in response to reduced renal blood flow
- Increased clotting time
- Predictable Intrinsic hepatic toxicity
- Unpredictable Idiosyncratic hepatic toxicity
- Can cause abortion and fetal malformations
caution: in horses, they are associated with right dorsal colitis
What are the contra-indications to using NSAID’s in a patient?
- GI Disease
- Impaired hepatic or renal function
- Dehydration/ hypovolemia/ hypotensive
- Coagulopathies
- Receiving other NSAIDs or corticosteroids
- Pregnant or lactating
- Neonates (< 8weeks old)
How can NSAIDs be classified?
- Based on Physiochemical properties
- According to their action on COX
What are the Non-selective NSAIDs? (3)
Phenylbutazone aka “bute”
Flunixin
Ketoprofen: licensed for use in pigs
What are the COX-2 selective NSAIDs? (3)
Meloxicam (Metacam)
Carprofen (Rimadyl)
Robenacoxib (Onsior)
What is the dual inhibitor NSAID? (1)
Tepoxalin
What are the 9 considerations before administering NSAID’s?
1) obtain complete history and previous use of NSAIDs or steroids
2) Assess patient: dehydration, cardiac, hepatic and renal dysfunction
3) Provide verbal and written client instructions
4) Recognize side effects and withdraw treatment
5) Perform regular hepatic and renal tests to assess toxicity/ damage
6) Use a balanced, integrated analgesic approach
7) Consider washout periods when changing drugs (7 day or more washout period)
8) Use gastroprotectants
9) Optimize the dose- titrate to the lowest effective dose
How long MUST the washout period be before using NSAIDs on an animal that was given Aspirin?
10 days from last dose
This is why it is not recommended owners treat with Aspirin at home, as NSAIDs cannot be used for 10 days
What species is Phenylbutazone used in?
Horses: for acute pain
Can Phenylbutazone be used in food-producing animals?
No! It is illegal in animals intended for human consumption
What species is Flunixin meglumine used in?
Horses:
- Analgesic especially for colic pain
- Anti-inflammatory
- Anti-endotoxic
What species is Meloxicam used in?
Licensed for use in dogs, cats, horses, cattle: chronic pain management
note: specific dose for cats due to their reduced ability for glucuronidation
What species is Carprofen used in?
Dogs, cats, horses
note: cats have a longer elimination half life
