Clinical Pharmacology of Alimentary

Question 1

drugs for acid suppression

Answer 1

antacids
h2 receptor antagonists
proton pump inhibitors

Question 2

drugs effecting GI motility

Answer 2

anti emetics
anti-muscarinics
anti-motility

Question 3

drugs for IBD

Answer 3

aminosalicylates
corticosteroids
immunisuppressants
biologics

Question 4

drugs affecting intestinal secretions

Answer 4

bile acids sequestrants and ursodeoxycholic acid

Question 5

what do antacids contain?

Answer 5

magnesium or aluminium

Question 6

what do antacids do?

Answer 6

neutralise gastric acid

Question 7

when should you take antacids?

Answer 7

when symptoms occur

Question 8

what is the function of alginates?

Answer 8

forms a viscous gel that floats on stomach contents and reduces reflux

Question 9

function of h2 receptor antagonists?

Answer 9

block histamine receptor thereby reducing acid secretion

Question 10

function of proton pump inhibitors

Answer 10

block proton pump and thereby reduce acid secretion

Question 11

does prokinetic agents increase or decrease gut motility and gastric emptying

Answer 11

increase

Question 12

what is the mechanism of action of GI motility?

Answer 12

invoolved parasympathetic nervous system control of smooth muscle and sphincter tone

Question 13

what is the mechanism of action for drugs that decrease motility?

Answer 13

via opiate receptors in GI tract to decrease ACh release

decrease smooth muscle contraction and increases anal sphincter tone

Question 14

what are the three mechanisms of anti-spasmodics

Answer 14

Anti-cholinergic muscarinic antagonists (hyoscine buscopan, mebeverine)
inhibit smooth muscle constriction in the gut wall, producing muscle relaxation and reduction spasm.

Direct smooth muscle relaxants

Calcium-channel blockers (peppermint oil) reduce calcium required for smooth muscle contraction

Question 15

what are the 4 types of laxatives?

Answer 15

bulk- isphagula
osmotic- lactulose
stimulant- senna
softners- arachis oil

Question 16

issues of laxatives

Answer 16

obstruction

route of administration-oral or rectal

need for other measures

misuse

Question 17

concerns and contraindications for corticosteroids

Answer 17

Osteoporosis
Cushingoid features including weight gain, DM, HT,
Increased susceptibility to infection
Addisonian crisis with abrupt withdrawal

Question 18

function of immunosuppressants

Answer 18

prevents the formation of purines required for DNA synthesis so reduces immune cell proliferation

Question 19

contraindications of Infliximab

Answer 19

Current TB or other serious infection
Multiple sclerosis
Pregnancy/breast feeding

Question 20

adverse effects of Infliximab

Answer 20

Risk of infection, particularly TB so all patients should be screened
Infusion reaction (fever, itch)
Anaemia, thrombocytopenia, neutropenia
?Demyelination
Malignancy

Question 21

drugs affecting biliary secretions

Answer 21

cholestryamine

ursodeoxycholic

Question 22

function of cholestryamine?

Answer 22

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

May affect absorption of other drugs so should be taken separately

May affect fat soluble vitamin absorption so may decrease vitamin K levels (affecting clotting and warfarin)

Question 23

what is ursodeoxycholic acid used to treat?

Answer 23

gallstones and primary biliary cirrhosis

Question 24

function of ursodeoxycholic acid?

Answer 24

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

Question 25

what processes can GI or liver disease affect?

Answer 25

absorption distribution metabolism excretion

Question 26

what are the problems with distribution?

Answer 26

low albumin

Question 27

what are the problems with metabolism?

Answer 27

liver enzymes- toxicity increased gut bacteria gut wall metablism- disease may reduce first pass metabolism

Question 28

what are the problems with biliary excretion

Answer 28

biliary excretion

Question 29

what are the changes to gut bacteria from GI adverse effects

Answer 29

Mainly antibiotics Loss of OCP activity Reduced vitamin K absorption (increased prothrombin time) Overgrowth of pathogenic bacteria (e.g. Clostridium difficile)

Question 30

what would be a type A ADR?

Answer 30

intrinsic hepatoxicity

Question 31

what would be a type B ADR?

Answer 31

idiosyncratic hepatoxicity

Question 32

risk factors for drug induced liver injury

Answer 32

``` age sex- female alcohol consumption genetic factors malnourishment ```

Question 33

what drugs should you not give to patient with liver disease?

Answer 33

drugs which are hepatic drugs which may worsen the non-liver aspectw of liver disease drugs which can be toxic due to changes in pharmacokinetics

Question 34

what effect can aspirin and NSAIDs have with bleeding?

Answer 34

increase bleeding time

Question 35

what effect can have NSAIDs have on ascites?

Answer 35

worsen due to fluid retention