Drug therapies for gastrointestinal disorders

Question 1

What part of the brain stem is responsible for the emetic effect (being sick)?

Answer 1

Medulla oblongata
There is a ‘vomiting centre’ that contains muscurinic receptors, when stimulated triggers vomitting.

Question 2

What is the chemoreceptor trigger zone and where is it?

Answer 2

Close to the medulla oblongata, outside the BBB
Triggered by chemicals
Have dopamine and serotonin receptors

Question 3

What are PPI’s (proton pump inhibitors) used for?

Answer 3

Acid reflux, heartburn, prevent and treat peptic ulcers

Oral or IV meds

Question 4

What are the suffix for PPI medications?

Answer 4

“-prazole”

E.g:
Omeprazole
Dexlansoprazole
Lansoprazole
Pantoprazole

Question 5

How do proton pump inhibitors work?

Answer 5

Reduce the amount of stomach acid being produced.

Question 6

What cells in our stomach are responsible for the production and release of stomach acid?

Answer 6

Parietal cells

Question 7

What stimulates the parietal cells in the stomach and what happens when they are stimulated?

Answer 7

Gastrin, Histamine, Acetylcholine.

The parietal cells release protons into the stomach via the proton pump.

Question 8

What does the proton pump do?

Answer 8

-Acts to move protons in the stomach.
-Move potassium into the parietal cells

These protons combine with chloride ions to form hydrochloric acid.

Question 9

How are PPI’s activated?

Answer 9

By the acidic environment of our stomach.

Question 10

What do PPI’s do?

Answer 10

Bind to the proton pump, inhibiting the proton production therefore reducing the HCL volume and the acidity of the stomach.

Question 11

How long does it take PPI’s to reach maximum effect?

Answer 11

2-3 days.

Question 12

How long do the affects of each does of a PPI last?

Answer 12

Approximately 1-2 days

Question 13

Why shouldn’t pts suddenly discontinue the usage of PPI’s?

Answer 13

There is a risk of rebound affect (increased acid reflux)

Make sure pt gradually starts coming off meds.

Question 14

What are the side effects of short term PPI usage?

Answer 14

Headaches
Diarrhoea
Abdominal pain
Nausea

Question 15

What are the long term side effects of PPI usage? (1% risks)

Answer 15

1. C.diff infections - pneumonia, fevers, diarrhoea - this is because low stomach acid will reduce immune function.
2. Deficiency of Vitamins B12, Mg, Fe, Ca - this is because low stomach acid means low nutrient absorption; leading to osteoporosis and hip fractures.

Question 16

What are antacids?

Answer 16

Ant = Against Acid = Acid

Question 17

What is the mechanism of action for antacids?

Answer 17

Antacids work as a base to neutralise any excess hydrochloric acid.

Question 18

What are the medication names and suffixes of antacids?

Answer 18

Suffix = carbonate or hydroxide

E.g:

Sodium bicarbonate
Calcium carbonate
Aluminum hydroxide
Magnesium hydroxide

Question 19

What requires the usage of antacids?

Answer 19

Acid reflux
Peptic ulcers

Question 20

What are the side effects of antacids?

Answer 20

Calcium and Aluminium meds cause ConstipAtion.

Magnesium meds cause GI upset and diarrhoea

Question 21

What are the two types of stool softening laxatives?

Answer 21

Docusate sodium
Docusate calcium

Question 22

How do laxatives work?

Answer 22

They draw water into the stool, which helps soften the stool.

Question 23

What are the side effects of laxatives?

Answer 23

Mild cramping
Diarrhoea

Question 24

What are the two types of bulk forming laxatives?

Answer 24

Psyllium
Methylcellulose

Used for constipation and chronic diarrhoea

Question 25

What is the mode of action of bulk forming laxatives?

Answer 25

Combine with water in intestines to soften stool and increase the bulk of the stool.

Question 26

What are the two types of stimulating laxatives?

Answer 26

Bisacodyl
Sennosides

Question 27

What is the mode of action for osmotic laxatives?

Answer 27

They work by drawing water into the intestine