Alimentary Pharmacology

Question 1

What drugs are used for acid suppression?

Answer 1

Antacids
Alginates
H2 receptor antagonists
Proton pump inhibitor

Question 2

What drugs affect GI motility?

Answer 2

Anti-emetics
Anti-muscarinics (anti-spasmodics)
Anti-motility

Question 3

What drugs are used in IBD?

Answer 3

Aminosalicylates
Corticosteroids
Immunosuppressants
Biologics

Question 4

How do antacids work?

Answer 4

Neutralise gastric acid, contain Mg or Al (Maalox)

Question 5

How do alginates work?

Answer 5

Form a viscous gel that frats on stomach contents, reduces reflux (Gaviscon)

Question 6

How do H2 receptor antagonists work?

Answer 6

Block histamine receptor, reduces acid secretion

Question 7

How are H2 receptor antagonists administered?

Answer 7

Oral or IV

Question 8

How do proton pump inhibitors work?

Answer 8

Block proton pump (K+/H+ pump), reduces acid secretion

Question 9

How are proton pump inhibitors given?

Answer 9

Oral or IV (Omeprazole)

Question 10

What are the complications of proton pump inhibitors?

Answer 10

GI upset
Predisposition to c diff infection
Hypomagnesaemia
B12 deficiency

Question 11

Name drugs which increase GI motility

Answer 11

Metoclopramide

Domperidone

Question 12

How does domperidone affect GI motility?

Answer 12

Blocks dopamine receptors which inhibit post synaptic cholinergic neurones

Question 13

Name drugs which decrease GI motility?

Answer 13

Loperamide

Opioids

Question 14

How do loperamide and opioids work to decrease GI motility?

Answer 14

Action is via opiate receptors in GI tract to decrease ACh release, thereby muscle contraction

Question 15

How do anti-spasmodics work to affect GI motility?

Answer 15

Anti cholinergic muscarinic antagonists inhibit smooth muscle constriction, producing muscle relaxation and reduction spasm
Smooth muscle relaxants
Calcium channel blockers reduce calcium required for muscle contraction

Question 16

What are the 4 types of laxatives?

Answer 16

Bulk (Isphagula)
Osmotic (Lactulose)
Stimulant (Senna)
Softeners (Arachis oil)

Question 17

How do laxatives work?

Answer 17

Increasing bulk, drawing fluid into gut and softening stool

Question 18

What are the issues with laxatives?

Answer 18

Obstruction (can rupture colon)

Misue

Question 19

What are the main aminosalicylates?

Answer 19

Mesalazine

Olsalazine

Question 20

How are aminosalicylates administered?

Answer 20

Oral

Rectal

Question 21

What are the adverse affects of aminosalicylates?

Answer 21

GI upset
Blood dyscrasia
Renal impairment

Question 22

How are corticosteroids administered?

Answer 22

Oral
IV
Rectal

Question 23

What are the contraindications of corticosteroids?

Answer 23

Osteoperosis
Cushingoid features (weight gain)
Increased susceptibility to infection
Addisonian crisis in abrupt withdrawal

Question 24

How do immunosuppressants work in IBD?

Azathioprine

Answer 24

Prevent the formation of purines required for DNA synthesis, reduces immune cell proliferation

Question 25

What are the adverse affects of immunosuppressants?

Answer 25

Bone marrow suppression Azathioprine hypersensitivity Organ damage (lung, liver, pancreas) Numerous drug interactions

Question 26

How do biologics work in IBD? (Inflixamab)

Answer 26

Prevents action of TNFalpha

Question 27

What are the contraindications of Inflixamab?

Answer 27

Cannot be used when pregnant, breast feeding, have a serious infection, TB or multiple sclerosis

Question 28

What are the adverse affects of Inflixamab?

Answer 28

``` Risk if infection Infusion reaction Anaemia Thrombocytopenia Neutropenia ```

Question 29

What drugs are used to control biliary secretions?

Answer 29

Cholestyramine | Ursodeoxycholic acid

Question 30

How does cholestyramine work to control biliary secretions?

Answer 30

Reduces bile salts by binding with them in the gut then excreting as an insoluble complex

Question 31

What are the adverse affects of cholestyramine?

Answer 31

May affect absorption of other drugs | May affect fat soluble vitamin absorption, decrease levels of vitamin K her fore affecting clotting and warfarin

Question 32

How does ursodeoxycholic acid work to control biliary secretions?

Answer 32

Inhibits enzyme involved in formation of cholesterol, altering amount in bile and slowly dissolving non calcified stones

Question 33

What are the main gastrointestinal adverse affects due to drugs?

Answer 33

``` Diarrhoea Constipation Bleeding Ulceration Changes to gut bacteria Drug induced liver injury ```

Question 34

What are the risk factors for drug administration?

Answer 34

``` Age (elderly) Sex (female) Alcohol consumption Genetic factors Malnourishment ```