GI Drugs (final exam) Flashcards
Centrally-acting emetics control vomiting through what three structures?
Vomiting (emetic) center
Chemoreceptor Trigger Zone (CRTZ)
Vestibular apparatus
What is unique about feline emetic receptors?
Cats have more a2 and 5-HT receptors
Also fewer D2 and H1 than dogs
Apomorphine mechanism of action
D2 agonist in Chemoreceptor Trigger Zone
What is the emetic drug of choice in dogs?
Apomorphine
Apomorphine adverse effects
Respiratory depression on overdose
Reverse with naloxone (will not reverse emetic effect)
Xylazine mechanism of action
A2 agonist in vomiting center and Chemoreceptor Trigger Zone
What is the emetic drug of choice in cats?
Xylazine
Why is Xylazine more effective in cats?
Cats have more a2 receptors than D2 receptors.
3% hydrogen peroxide mechanism of action
Direct irritation of oropharynx and GI lining
Hydrogen peroxide uses
Emesis in dogs (NOT cats)
Owner can administer at home
Hydrogen peroxide contraindications
Cats, risk of hemorrhagic gastroenteritis
Pre-existing GI ulcers/bleeding
What are the physiological inhibitors of appetite?
Serotonin
Cortisol releasing hormone
What are the physiological stimulants of appetite?
Norepinephrine Dopamine GABA agonists Ghrelin Serotonin antagonists
Mirtazapine mechanism of action
Serotonin antagonist
Inhibits satiety
Mirtazapine uses
Dogs > cats (both unreliably)
Variable onset
Cyproheptadine mechanism of action
Serotonin antagonist
Inhibits satiety
Cyproheptadine uses
Cats, more effective than dogs
Onset 2-3 days
Sedation is most common side effect
Capromorelin mechanism of action
Ghrelin receptor agonist (selective)
Capromorelin use
Increase ghrelin -> stimulate hypothalamus, increase appetite
Antiemetics
Maropitant citrate
Ondansetron
Dolasetron
Metoclopramide
Maropitant citrate mechanism of action
Blocks substance P
Neurokinin receptor antagonist (NK1)
Vomiting center and Chemoreceptor Trigger Zone
Maropitant citrate uses
Antiemetic in cats and dogs
Motion sickness in dogs