pharmacology of intestinal motility secretion, nausea and vomiting

Question 1

what is vomiting

Answer 1

a defence mechanism triggered by the vomiting/emetic centre located in the brain stem

Question 2

what may cause nausea and vomiting

Answer 2

anxiety 
motion sickness 
migraine 
pregnancy 
side effects of drugs

Question 3

what are the main neurotransmitter systems involved in nausea and vomiting

Answer 3

5-HT
dopamine
ACh

Question 4

what are the three main antiemetic drugs

Answer 4

> anti-histamines (H1 receptor antagonists)
antimuscarinics (muscarinic ACh receptor antagonists)
5-HT3 receptor antagonists
dopamine receptor antagonists
neurokinin-1 receptor antagonists

Question 5

examples of antihistamines

Answer 5

cyclizine
promethazine
diphenhydramine

Question 6

examples of antimuscarinics

Answer 6

scopolamine (hyoscine)

Question 7

examples of 5-HT3 receptor antagonists

Answer 7

ondansetron
granisetron
palonosetron

Question 8

examples of dopamine receptor antagonists

Answer 8

chlorpromazine
droperidol
haloperidol
prochlorperazine 
metoclopramide

Question 9

examples neurokinin-1 receptor antagonists

Answer 9

fosaprepitant

apreptant

Question 10

action of antihistamines

Answer 10

> act primarily as antagonists at histamine H1 receptors in the brain

Question 11

indications for antihistamines

Answer 11

indicated for nausea, vomitting > motion sickness

Question 12

side effects of antihistamines

Answer 12

sedation lol

Question 13

action of antimuscarinics

Answer 13

they act primarily as antagonists at muscarinic acetylcholine M1 receptors in the brain

Question 14

indications for antimuscarinics

Answer 14

motion sickness

Question 15

side effects of antimuscarinics

Answer 15

dry mouth
tachycardia
constipation

Question 16

action of 5-HT3 receptor antagonists

Answer 16

they act primarily as antagonists at 5-HT3 receptors in the chemoreceptor trigger tone of the medulla in the hindbrain
>also the 5-HT3 receptors in the GI tract

Question 17

side effects of 5-HT3 receptors antagonists

Answer 17

constipation
diarrhoea
headache

Question 18

action of dopamine receptor antagonists

Answer 18

they act primarily as antagonists at D2 receptors in the chemoreceptor trigger zone of the medulla in the hindbrain
>also D 2 receptors on the GI tract

Question 19

side effects of D2 receptor antagonists

Answer 19

diarrhoea and extrapyramidal side effects

Question 20

neurokinin-1 receptor antagonists mode of action

Answer 20

act as antagonists at NK1 receptors in the GI tract in the hindbrain blocking the effects of substance P

Question 21

side effects of Neurokinin-1 receptor antagonists

Answer 21

constipation and headache

Question 22

what are drugs that affect GI motility

Answer 22

antidiarrhoeal drugs

laxatives

Question 23

what are antidiarrhoeals

Answer 23

> they are electrolyte replacements
loperamide and diphenoxylate are opiates that has reduced effect on the brain
they are sometimes combines with atropine
high doses of loperamide have been associated with drug abuse
side effects include = constipation sedation respiratory depression

Question 24

what are laxatives

Answer 24

> ispaghula husk = bulk forming laxative
lactose = osmotic laxative (hepatic)
senna-stimulant purgative = increases electrolyte/water secretion