Pharmacology 1

Question 1

What are the aims when giving drugs to treat ulceration?

Answer 1

Inhibit acid secretion
Neutralise acid
Protect mucosa in duodenum

Question 2

How do NSAIDs cause stomach ulcers?

Answer 2

Reduces prostaglandin which
Reduces mucus production
Stomach digests itself

Question 3

What are two drug categories to prevent stomach ulceration?

Answer 3

Acid secretion inhibitors

Antacids (for already secreted acid)

Question 4

What are the 2 types of acid secretion inhibitors?

Answer 4

Proton pump inhibitors

Histamine 2 blocker

Question 5

How do histamine 2 blockers work? Give an example

Answer 5

Blocks histamine stimulation of proton pump

Ranitidine

Question 6

How do proton pump inhibitors work? Give an example

Answer 6

Bind to H+/K+/ATPase

Omeprazole

Question 7

How do locally acting antacids work?

Answer 7

Neutralise laminal acid
Inhibit peptin cleavage
Protect mucosa
Act as adsorbent
Stimulate prostaglandins (mucus production)

Question 8

Give 2 examples of locally acting antacids

Answer 8

Magnesium salts

Aluminium salts

Question 9

Antacids can also be gastric protectives. What are these? and how do they work? Give an example

Answer 9

Viscous, acidic gels
Bind to ulcer and protect from acid
Sucralfate

Question 10

Where is the vomiting centre?

Answer 10

Medulla oblongata

Question 11

When may emetics may be given?

Answer 11

After toxic ingestion

Prior to GA

Question 12

Why do animals need starving before GA?

Answer 12

Anaesthetic inducing drugs stimulate vomiting

Causes inhalation pneumonia

Question 13

Vomiting can be either centrally or peripherally stimulated. Where causes this stimulation?

Answer 13

Chemoreceptor trigger zone
GI tract
Vestibular apparatus

Question 14

Vomiting due to GI tract stimulation acts via which pathways?

Answer 14

Vagal sympathetic

Question 15

Vomiting due to vestibular apparatus stimulation is via what afferent pathways?

Answer 15

Cholinergic/histaminic afferent pathways

Question 16

How do centrally acting emetics work? Give a drug example

Answer 16

Stimulate chemoreceptor trigger zone

Apomorphine

Question 17

How do peripherally acting emetics work?

Answer 17

Stimulate vagal sympathetic afferent receptors in pharynx or stomach

Question 18

Give 2 examples of peripherally acting emetics

Answer 18

NaCl

Bicarbonate of soda

Question 19

Why my anti-emetics be given? What needs to be established before giving anti-emetics?

Answer 19

Prolonged vomiting causes acid/base imbalance and dehydration
Diagnosis

Question 20

What are the 4 classes of anti-emetics? (NAAA)

Answer 20

Neurokininin-1 antagonists
Antihistamines
Anticholinergics
Antidopaminergic agent

Question 21

How do antihistamines work as antiemetics? Give an example

Answer 21

Block histaminergic and cholinergic afferent pathway from vestibular organs to vomit centre
Diphenhydramine

Question 22

How do anticholinergics work?

Give an example

Answer 22

Block cholinergic afferent pathway from GI tract to vomiting centre
Propantheline

Question 23

How do antidopaminergic drugs work? Give an example

Answer 23

block dopamine receptors in chemoreceptor trigger zone

Phenothiazines

Question 24

How do neurokinin-1 antagonists work?

Answer 24

Block binding of substance P= inhibits vomiting

Maropitant

Question 25

What are cathartics?

Answer 25

Drugs that accelerate defaecation

Question 26

When may cathartics and laxatives be used?

Answer 26

Relieve constipation Remove toxic ingestants Prevent tenesmus (incomplete defaecation) Evacuate bowel prior to surgery/radiography

Question 27

What are classes of drugs that act as laxatives/cathartics?

Answer 27

``` Osmotic cathartics Irritant cathartics Bulk laxatives Lubricants Surfactants ```

Question 28

How do osmotic cathartics work? | E.G?

Answer 28

Non-absorbable - increase osmotic pressure and water retention in lumen Gut responds by increasing contractions to expel material Lactulose

Question 29

Give two examples of osmotic cathartics

Answer 29

``` Lactulose Magnesium sulphate (Epsom salts) ```

Question 30

How do irritant cathartics work? Give an example

Answer 30

Reduce fluid absorption Stimulate peristalsis Castor oil

Question 31

How do bulk laxatives work? Give an example

Answer 31

Contain hydrophilic colloids that absorb water Stimulates peristalsis E.g. sterculia

Question 32

What do lubricants do? Give an example

Answer 32

Lubricate and soften faeces | Liquid paraffin

Question 33

What do surfactants do? Give an example

Answer 33

Hydrate and soften faeces - cathartic | Docusate