Emetics & Anti Emetics

Question 1

Emetics

Answer 1

1. Centrally acting:
   Apomorphine and morphine
2. Peripherally acting:
   Mustard, sodium chloride, tartrate
3. Both
   Ipecacuanha

Question 2

Anti-emetic

Answer 2

1. Anti cholinergics
   Hyoscine and dicyclomine
2. H1 antihistamine
   •Promethazine
   •Cyclizine
   •meclozine
   •cinnarizine
3. Dopamine receptor antagonist:
   Chlorpromazine
   Prochlorperazine
   Domperidone
   Haloperidol
4. 5HT3 antagonists
   Ondansetron, granisetron, dolasetron
5. Pro-kinetic drug
   metoclopramide, domperidon, cisapride, zacopride, erythromycin, azithromycin
6. Adjuvant drugs
   • dexamethazone
   • lorazepam
   •Nabilone

Question 3

5 HT3 antagonists

Answer 3

Drugs: ondansetron, granisteron, dolasetron

P.K; rapidly absorbed, metabolised in the liver and excreted in urine and feces

MOA: suppress N and V by blocking the serotonin receptors in the CTZ and afferent Vagal nerve terminals in upper GI tract

Uses: chemotherapy induced nausea and vomiting. 30 mins before chemotherapy
Postoperative and postradiation nausea and vomiting

Adverse effects:
• excellent safety profile
• headache and constipation (common side effect)
• all three drugs cause prolongation after QT interval but more pronounced with dolasetron

Question 4

Ondansetron

Answer 4

Uses: in vomiting and nausea associated with cytotoxic agents and radiotherapy

Pk: plasma half life: 3-4 hr, metabolised in liver, less than 10% excreted unchanged in urine

Caution: patient with liver damage