NSAIDs Dr. Ambrisko Flashcards
What are NSAIDs
aka?
Non-Steroidal Anti Inflammatory Drugs
NSAIA = Non-Steroidal Anti Inflammatory Analgesics
What are the effects of NSAIDs?
Analgesia
anti-inflammatory
antipyretic
What is the clinical use of NSAIDs
Suitable for mild to moderate post op pain
Mechanism of action of NSAIDs
Remember that inflammatory mediators play a role in pain development
COX & LOX inhibition
What are the types of COX enzymes
COX-1: constitutive
COX-2: inducible
What is the importance of COX-1
Important for normal function of:
GI tract (mucosal protection)
Platelets
Kidneys
Inhibition ⇒ lead to side effects
What is the importance of COX-2
Inducible
in response to inflammation
→ pain
Selective inhibition desirable
Good COX Bad COX therory
logical to assume
- good COX-1 inhibition bad*
- bda COX-2 inhibition good*
COX-2 inhibitors have less side effects but, not devoid of them
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Whats wrong with good COX bad COX theory
In vitro experiments with COX selecitvity are ambiguous
COX-2 enzyme may also be constitutive
PK of drugs may play important role
Side effects of NSAIDs
NSAIDs largest group of veterinary drugs having adverse effects reported to FDA
GI effects
hemostatic abnormality
renal impariment
hepatotoxicity
impairment of cartilage synthesis
Mechanism of renal damage by NSAIDs
in cases of hypovolemia, hypotension PGs keep GFR up
COX-1 & -2 inhibitors may impair this
potentially dangerous under anesthesia due to vasodilation & hypotension caused by anesthetics
Peri OP use of NSAIDs
Concerns: if hypotension/hypovolemia develops renal damage likely
Compromise: safer to give NSAIDS right before the end of surgery
Assumes: opioid analgesia is provided at least from induction until the beginning of NSAID analgesia
Contraindications of NSAIDs
Hypovolemia, hypotension
kidney dz
hemostatic abnormality
pregnancy - PGs keep ductus arteriosus open in fetus
Very young or old
concomitant glucocorticoid therapy
Considerations for Chronic NSAID therapy
Cats: meloxicam
Pt selection important
Regular lab work - blood & urine
Dose for lean bodyweight
lowest dose - shortest necessary duration
if the animal stops eating STOP NSAID
Cats are special when using NSAIDs
metabolize certain drugs slower
accumulation of toxic drugs
inter-individual differences
liquid formulation preferred!
FDA approved NSAIDs for Cats
Meloxicam
Robenacoxib
Carprofen
Preferential COX-2 inhibitor
renal damage is rare but possible
NOT approved for cats!
Meloxicam
Preferential COX-2 inhibitor
Approved in cats for chroni tx
Robenacoxib (Onsior)
Selective COX-2 inhibitor
Approved for cats up to 3 days post op
Approved for dogs post op & chronic
Other selective COX-2 inhibitors coxibs
Dercoxib
firocoxib
similar to robenacoxib
Phenylbutazone
Non-selective COX inhibitor
horses & cattle not SA
Flunixin meglumine
Non-selective COX inhibitor
horses & cattle
similar to phenybutazone
Ketoprofen
Non-selective COX inhibitor
mostly for horses but can be used SA (not best choice)
Acetylsalicylic acid (Aspirin)
Non-selective
Side effects common & serious
NOT FDA approved
cats antithrombotic agent
Acetaminophen (Tylenol)
NOT approved for veterinary patients
Toxic in cats (methemoglobinemia)
Contraindicated in cats!!
