NSAIDs Flashcards
Define pharmacokinetics
What the body does to the drug
Define pharmacodynamics
What the drug does to the body
What is the therapeutic window of NSAIDs?
Narrow
What do NSAIDs block?
Prostaglandins
Where do NSAIDs act? (2)
- Periphery
- Spinal cord
Where do steroids act in the pathway? What is the negative of this?
At phospholipase, which is one stage higher than NSAIDs and you therefore get more side effects
Where do NSAIDs act in the pathway?
Cyclooxygenase
Name 5 things NSAIDs have been shown to inhibit in horses (7)
–Inflammation
–Fever
–Oedema
–‘Endotoxaemia’ (??)
–Ileus
–Adhesion formation
–(thrombosis formation)
Which NSAID can we use in inflammatory visceral disease in equine?
Flunexin
What can occur with poor IV administration of phenylbutazone?
Thrombophlebitis and necrosis
What must you do if you give a horse phenylbutazone?
Sign the horse passport out of the food chain
What should you do if you want to give phenylbutazone but there is no passport available?
Use meloxicam as this can go into food chain
Compared with opioids, what is NSAIDS:
A) Better for?
B) Less good for?
A) MSK Pain
B) Visceral pain
Name 2 reasons we would rather use NSAIDs than opioids in horses?
Side effects
Don’t want to dispense too many opioids (horse owners are dodge)
Name 7 pracitcal considerations when it comes to NSAID use (9)
- Non-scheduled (still POM-V)
- Cheaper vs opioids
- Effective per-os
- Little long-term decrease in efficacy
- Longer duration of action
- Side effects
- Compliance (owner)
- Cost
- Co-morbidities
Where are NSAIDs metabolised?
Liver
Where are NSAIDs excreted?
Kidneys
What is the protein binding of NSAID?
High
What is the volume of distribution of NSAIDs?
Low
What is the wash out period?
–If you want to change from one NSAIDs to another. There is advice to allow a number of half life wash out before we start the next one. May need bridging medication to tide them over e.g. adjuncts – paracetamol. Not currently done in horses.
What should you do if you have a problem with an NSAID?
Yellow form or online reporting to VMD
What is the “housekeeping” pathway?
Cox 1 - constitutive
What is the inflammatory pathway?
COX 2 - inducible
Why can NSAIDs cause problems with the kidneys?
- Renal blood flow mediated by prostaglandins (PG) in medullary circulation (Therefore PG inhibition by NSAIDS can cause problems)
- Hypotension + NSAID = renal damage hence concern peri-operatively
What is the effect of prostaglandins in the GIT?
They are cytoprotective
–Decrease the volume, acidity and pepsin content in the stomach
–Stimulate bicarbonate secretion
–Promote mucosal blood flow and repair and turnover of cells
Name 5 side effects of NSAIDs (7)
–Vomiting (small ans)
–Colic
–Inappetance
- D++
–PLE
-2° anaemia,
–Ulceration
–Death
What are young horses more susceptible to with NSAIDs?
Gastric ulceration
What are adult horses with NSAIDs more susceptible to?
Right dorsal colitis
What is the relative ulcerogenicity with:
Flunixin
Phenylbutazone
Ketoprofen?
Phenylbutazone > flunixin > ketoprofen
Name 2 long term adaptations of the GI tract to NSAIDs (3)
- Increased mucosal blood flow
- Increased mucosal cell regeneration
- Decreased inflammatory cell infiltrate
How many days on NSAIDs does it take for there to be long term adaptation?
14 days
What is enterohepatic recycling?
Excretion into intestine from bile – repeated exposure of the duodenum to drug
What does enterohepatic recycling directly correlate to?
Toxcitiy
Name 4 ways GI safety with NSAIDs can be improved (6)
–Protective strategy – case by case basis
–Sucralfate (sucrose aluminum sulphate)
–H2 antagonists
–Proton pump-inhibitors
–? Newer Coxibs ?
–Different formulation of NSAIDs sometimes
What is the effect of some NSAIDs on cartilage and what is the mechanism of this?
Worsen cartilage degeneration in arthritic animals – decreased GAG synthesis
What is the effect of carprofn on equine cartilage cells? (2)
- Increased GAG at therapeutic doses
- Increase proteoglycan metabolism
What type of reactions happen with NSAIDs causing hepatotoxciity?
Type 1 and type 3
What is the breed predisposition of dogs getting hepatotoxcity with NSAIDs?
There isn’t one
What is the difference between cats and dogs having NSAIDs?
They have a lower clearance of salicylates
Name 5 of the possible effects cats may get with NSAIDs (7)
- Hyperthermia
- Respiratory alkalosis
- Metabolic acidosis
- Methaemoglobinaemia
- Haemorrhagic gastro-enteritis
- Renal failure
- Hepatic injury
What is Robenacoxib (onsior)?
A tissue selective NSAID
Name 5 guidelines for safe use of NSAIDs? (7)
–No hypovolaemia (but what about colic sx?)
–No concurrent administration of another NSAID OR a steroid – possibly allow washout (4-5 half lives?? in dogs), but this is not performed in horses..
–No hepatic or renal insufficiency
–Dog – high confidence in absence of renal failure
–Cats – no margin of safety !
–Routine biochemistry? For long term use? YES
–Screening biochemistry? Before starting in some cases of long term therapy? YES IF POSSIBLE
What is acetaminophen?
Paracetamol
Where is paracetamol licensed?
Pigs
When is paracetamol most commonly used?
As a bridgng mechanism
Where is sodium salicylate licensed?
Catlle and pigs
What is the mechanism of paracetamol action?
–Unknown mechanism of action – central ?, 5-HT3, TPRV1, Cox, cannabinoid pathways possibly involved?
Where should you look for off licence use of NSAIDs?
BSAVA formulary
What is the issue of using NOAH for drugs?
Not all drugs are in there - companies have to pay to be in there
Name 4 licensed NSAIDs in horses (6)
- Phenylbutazone,
- Suxibuzone,
- Flunixin,
- Meloxicam,
- Vedaprofen,
- Firocoxib
Name 3 licensed NSAIDs in cats (4)
- Meloxicam,
- Robenacoxib,
- Ketoprofen,
- Tolfenamic acid
Name 7 licensed NSAIDs in dogs (10)
- Meloxicam,
- Carprofen,
- Robenacoxib,
- Mavacoxib,
- Paracetamol (with codeine),
- Tolfenamic acid,
- Ketoprofen, (tepoxalin - expired )
- Firocoxib,
- Phenylbutazone,
- Cimicoxib
Name 4 licensed NSAIDs in pigs (6)
- Ketoprofen,
- Meloxicam,
- Tolfenamic acid,
- Flunixin,
- Salicylic acid,
- Paracetamol
Name 3 licensed NSAIDs in cows (4)
- Ketoprofen,
- Meloxicam,
- Flunixin,
- Salicylic acid
Name licensed drugs in sheep and goats
Nothing licensed – use cascade as for other food producing animals
What is the benefit of mavacoxib?
Duration up to a month
Name 6 therapeutic decsions of using NSAIDs (8)
- Consider Efficacy
- Consider Safety
- Address compliance (see suggestions in the OA NSAID booklet for improvements)
- Consider the formulation – route of admin
- Cost ?
- Duration of action
- Support packages?
- EBM
Name 8 “other” therapies to NSAIDs for MSK disease (10)
- Exercise management
- Weight control & diet (may need additional analgesics
- Modifications to lifestyle (ramps, rugs, claws)
- Hydrotherapy & physiotherapy
- Chondroprotectives
- Joint replacement
- IRap
- Stem cell therapies
- Other ‘drugs’ :Isoxsuprine hydrochloride (Navilox), vegetable tablets, garlic & fenugreek, sodium hyaluronate (Hyonate), prednoleucotropin (PLT)
- EP4 receptor blockers (galliprant –USA only, UK 2018/19)