Emetics and anti-emetics Flashcards
What are the 2 main drugs used to induce emesis in small animals?
Xylazine and apomorphine
What is the mechanism of action of xylazine?
a2-adrenoceptor agonist, binds to receptors in CTZ
How is xylazine administered?
I.V. or I.M.
What is the main use of xylazine?
Emetic in cats
What are the side effects associated with xylazine?
Sedation
What is the mechanism of action of apomorphine?
Dopamine agonist, binds to receptors in CTZ
How is apomorphine administered?
Parentrally (tablet can be placed under eye and removed once vomiting begins)
What is the main use of apomorphine?
Emetic in dogs
What are the side effects associated with apomorphine?
Protracted vomiting, excitement, restlessness
In which species should vomiting never be induced?
Horses and rabbits
What are the 4 therapeutic options for preventing emesis?
Phenothiazines, metoclopramide, neurokinin antagonists, 5HT3 antagonists
What is the mechanism of action of phenothiazines?
D2 antagonist
Describe the pharmacokinetics of phenothiazines
- Oral administration
- Well absorbed and distributed
- Excreted by kidneys
What are the main uses of pheothiazines?
- Broad spectrum anti-emetic
- Sedative
What are the side effects associated with phenothiazines?
Hypotension, bradycardia, sedation
What is the mechanism of action of metoclopramide?
D2 antagonist
Describe the pharmacokinetics of metoclopramide
- Oral, I.M., subcutaneous or slow I.V. administration
- 1st pass metabolism
- Excreted by kidneys
What are the side effects associated with metoclopramide?
Movement disorders and fatigue
What are the main uses of metoclopramide?
- Anti-emetic
- Gastric motility disorders
What is the mechanism of action of neurokinin antagonists?
Nk-1 receptor antagonist
Describe the pharmacokinetics of neurokinin antagonists
- Oral or subcutaneous administration
- Hepatic metabolism
What are the main uses of neurokinin antagonists?
Broad specturm anti-emetic
Are there any side effects associated with neurokinin antagonists?
Hypersalivation and diarrhoea
Describe the mechanism of action of 5HT3 antagonists
5HT3 antagonist
What are the main uses of 5HT3 antagonists?
Use if metoclopramide is uneffective
Are there any side effects associated with 5HT3 antagonists?
Usually well tolerated with few side effects