Chapter 23 NSAIDs Flashcards
What is the basic mechanism of action for NSAIDs?
Inhibition of the active binding site of cyclooxygenase (COX), involved in the formation of eicosanoids by oxidation of arachidonic acid.
What are the two isoforms of cyclooxygenase (COX)?
COX1 and COX2.
What is the role of COX1?
Referred to as the housekeeping isoform, it is continuously expressed in tissues like platelets, gastrointestinal mucosa, and kidneys.
What is the role of COX2?
Constitutively expressed in some tissues and inducible by pro-inflammatory signals, it is involved in inflammatory responses.
What is the significance of COX isoforms?
Differential binding of NSAIDs to COX1 versus COX2 explains the common gastrointestinal and renal side effects of non-specific COX inhibitors.
What are prostanoids?
Products of COX activity, including prostaglandins, thromboxane, and prostacyclin, involved in inflammation and regulation of physiological functions.
What is prostaglandin E2 (PGE2)?
A prostanoid involved in various functions like reducing gastric acid secretion, stimulating gastric mucus secretion, vasodilation, and increasing body temperature.
What is thromboxane A2 (TXA2)?
A product of COX activity primarily found in platelets, it is a potent vasoconstrictor and enables platelet aggregation.
What is prostacyclin (PGI2)?
A product of COX activity found in endothelial cells, functioning as a physiological antagonist to TXA2.
What are non-selective NSAIDs?
Drugs that inhibit both COX1 and COX2 enzymes.
What is phenylbutazone (bute)?
An enolic acid derivative and non-selective COX inhibitor, widely used for its analgesic and anti-inflammatory properties in horses.
What are the recommended doses for phenylbutazone?
4.4 mg/kg PO or IV BID as a loading dose and 2.2 mg/kg PO or IV BID to SID as a maintenance dose.
What are the common adverse effects of phenylbutazone?
Anorexia, depression, gastric and urinary bladder ulceration, renal papillary necrosis, neutropenia, anemia, protein losing enteropathy, colitis, and death.
What is flunixin meglumine?
A nicotinic acid derivative NSAID known for its potent analgesic effect in controlling acute visceral pain.
What is the recommended dose for flunixin meglumine?
1.1 mg/kg PO or IV BID as an anti-inflammatory dose.
What are the common side effects of flunixin meglumine?
Gastric ulceration and renal papillary necrosis.
What is aspirin (acetylsalicylic acid)?
A non-selective COX inhibitor used primarily as an antithrombotic agent due to its ability to irreversibly bind COX in platelets.
What is ketoprofen?
A propionic acid derivative and non-selective COX inhibitor with a long duration of action, often used once daily in horses.
What is the recommended dose for ketoprofen?
2.2 mg/kg IV SID for up to five days.
What are the common adverse effects of ketoprofen?
Gastric ulceration and renal toxicity.
What is naproxen?
A member of the propionic acid subclass of NSAIDs, characterized as a non-selective COX inhibitor.
What is carprofen?
A propionic acid derivative NSAID, with better analgesic than anti-inflammatory properties in horses.
What is meclofenamic acid?
An anthranilic acid derivative and non-selective COX inhibitor, available only in oral formulation for horses.
What is eltenac?
An acetic acid derivative NSAID, shown to be a non-selective COX inhibitor in horses.
What is the recommended dose for eltenac?
0.5 mg/kg IV SID.
What is vedaprofen?
An arylpropionate derivative NSAID, highly COX1-selective, used in horses.
What is firocoxib?
A second generation COX2 inhibitor, the first COX2-selective inhibitor approved for both oral and intravenous use in horses.
What is the recommended dose for firocoxib?
0.1 mg/kg PO or 0.09 mg/kg IV SID for up to 14 days.
What are the common adverse effects of firocoxib?
Gastric ulceration and nephropathy are significantly less likely compared to non-selective COX inhibitors.
What is meloxicam?
An enolic acid NSAID of the oxicam group, structurally similar to piroxicam, and a COX2 selective inhibitor.
What is the recommended dose for meloxicam?
0.6 mg/kg PO or IV SID.
What is deracoxib?
A diaryl-substituted pyrazole, structurally related to celecoxib, and a COX2 selective inhibitor approved for dogs.
What is etodolac?
An indole acetic acid derivative and COX2 selective inhibitor approved for use in dogs.
What is diclofenac sodium?
A phenylacetic acid derivative available in oral, intravenous, and topical formulations, used as an NSAID.
What is the effect of diclofenac when given orally to ponies?
Significant leukopenia and prolongation of prothrombin and activated partial thromboplastin times.
What are antihistamines used for in horses?
Most commonly used for allergic mediated skin disease.
What is hydroxyzine?
A first generation H1 receptor antagonist antihistamine, commonly used for chronic urticaria in horses.
What is chlorpheniramine?
A first generation H1 receptor antagonist antihistamine, with low bioavailability and reduced efficacy in horses.
What is diphenhydramine?
An ethanolamine derivative first generation antihistamine, used for immune-mediated dermatopathies and reversing extrapyramidal excitation induced by fluphenazine.
What is pyrilamine?
An ethylenediamine first generation antihistamine, the only antihistamine with label approval for use in horses in the United States.
What is doxepin?
A dibenzoxazepine derivative tricyclic antidepressant with antihistamine, anticholinergic, and alpha-adrenergic blocking effects.
What is cetirizine?
A second generation H1 receptor antagonist, a metabolite of hydroxyzine, used for insect bite hypersensitivity and eosinophilic keratitis in horses.
What is dimethyl sulfoxide (DMSO)?
A by-product of the wood and paper industry, used for its solvent properties and anti-inflammatory effects.
What are the unique properties of DMSO?
Rapid penetration of skin, mucous, and cell membranes, facilitation of other substances’ penetration, and inhibition or stimulation of enzymes.
What is the significance of flunixin meglumine in gastrointestinal disorders?
It is popularized for treatment of acute gastrointestinal disorders associated with endotoxemia.
What is the role of PGE2 in inflammation?
Up-regulation of inducible PGE2 biosynthesis explains the cardinal signs of inflammation: rubor, heat, pain, and swelling.
What is the impact of COX2 selective inhibitors on intestinal barrier function?
They do not delay mucosal recovery following ischemic injury, unlike non-selective COX inhibitors.
