Lecture Course 5: Diversity

Question 1

Aspirin

Answer 1

Salicyclate non specific COX inhibitor
Inhibits conversion of arachidonic acid (from plasma membrane) to prostaglandin G2 and therefore also downstream prostaglandins
Anti-inflammatory, anti-pyretic, analgesic, anti-thrombotic
Increases gastric acid secretion

Question 2

Caffeine

Answer 2

Methylxanthine

Non selective PDE inhibitor and adenosine A1 antagonist

Question 3

Carprofen

Answer 3

NSAID
Non selective COX inhibitor in humans
COX-2 (inducible) inhibitor in dogs and cats
Photoallergen in humans due to lack of fur

Question 4

Clenbuterol

Answer 4

B2 Agonist

Used in equine Chronic Obstructive Pulmonary Disease as causes bronchodilation

Question 5

Coumarin

Answer 5

Found in sweet clovers. Harmless.

Dimerises to form dicoumarol in spoiled clover silage which causes sweet clover disease in cattle (fatal bleeding)

Question 6

Etamiphylline

Answer 6

Xanthine cardiac and respiratory stimulant
Inhibits phosphodiesterase and antagonizes adenosine receptors
Causes bronchodilation, CNS and myocardial stimulation and diuresis

Question 7

Flunixin

Answer 7

NSAID in horses, cattle and pigs

Question 8

Ibuprofen

Answer 8

NSAID - Non specific COX inhibitor
Toxicity in dogs, cats and ferrets (most sensitive)
Causes kidney failure and gastric ulcers
Enterohepatic circulation - absorbed from GI into blood but excreted back into proximal GI in bile

Question 9

Ivermectin

Answer 9

Antihelminthic and antiarthropod- Induces flaccid paralysis by targeting glu-gated Cl- channels
Ivermectin sensitive GABA channels in brain are protected by BBB - pumped out by P-glycoprotein (aka. multidrug resistance -1a)
Collies, australian shepherds and border collies have a mutation mdr1a gene - sensitive to ivermectin

Question 10

N-acetyl Cysteine

Answer 10

Used in treatment of paracetamol overdose to replenish GSH, which aids in metabolism of paracetamol

Question 11

Paracetamol

Answer 11

Atypical NSAID - no anti-inflammatory action

No glucoronyl transferase in dogs and cats => accumulation of PAP => toxicity

Question 12

Phenylbutazone

Answer 12

NSAID (cox inhibition)
Very long half life in humans and in cows
Often used in horses - also present as active metabolite oxphenylbutazone

Question 13

Theobromide

Answer 13

Methylxanthine in chocolate
Inhibits PDE non specifically and antagonises Adenosine receptors: activates cardiac ryanodine receptors
Toxic to dogs - presents like caffeine intoxication (hyperexcitability, cardiotoxicity)
Long half life (18hr) - accumulation
Main metabolite = 3MX

Question 14

Theophylline

Answer 14

Methylxanthine

Question 15

Warfarin

Answer 15

Competitively inhibits Vit K Epoxide Reductase (VKORC1)
Removes negative charge from post-translationally modified glutamate
Necessary for factor 2, 7, 9, 10
VKORC1 mutations in rats => loss of OH group => loss of warfarin sensitivity