Antienemic drugs

Question 1

Vomiting Reflex (regions of brain)

Answer 1

Vomiting centre (VC)
●Medulla oblongata
●Coordinates muscles involved in vomiting

Chemoreceptor trigger zone (CTZ)
●Medulla oblongata
●Once stimulated, leads to vomiting reflex

Question 2

Most antiemetic drugs are..

Answer 2

Receptor antagonists (inhibit neurotransmitter action in vomiting reflex)

Question 3

5-HT (serotonin) antagonists

Answer 3

5-HT (serotonin) antagonists
-Block 5-HT receptots in CTZ, VC and GI
DRUG: Odansetron
Used in chemotherapy-induced nausea vomiting (CINV) and postoperative N&V

Question 4

Dopamine (DA) receptor antagonists

Answer 4

Dopamine (DA) receptor antagonists
-Block DA receptors in the CTZ
-Also used as antipsychotics and Prokinetic agents (Increase GI motility)
DRUG: Chlorpromazine

Question 5

Anticholinergic Agents

Answer 5

Anticholinergic Agents
-Block acetylcholine receptors in inner ear
DRUG: Scopolamine
Used for motion sickness as a patch behind ear

Question 6

Antihistamine Agents (H1 receptor antagonist)

Answer 6

**Antihistamine Agents (H1 receptor antagonist)
-Blocks H1 Receptor
-Also prevents cholinergic stimulation in vestibular and reticular areas

DRUG: Dimenhydrinate (gravol)
-Diphenhydramine and 8-chlorotheophylline

Question 7

Second-line drugs for N&V with chemotherapy

Answer 7

Nabilone and dronabinol (withdrawn in canada)

Question 8

Client Care in chemotherapy

Answer 8

Chemotherapy: anti-emetics often given 30 min to 3 hours before chemotherapy agent