25. Lower GI Pharmacology

Question 1

What drugs are used in the treatment of inflammatory bowel disease?

Answer 1

Aminosalicylates
Corticosteroids
Immunosuppressive agents
Antimicrobials
TNFa inhibitors

Question 2

When are aminosalicylates indicated?

Answer 2

Reduce symptoms of mild disease

Given for 4-6 weeks in UC to prevent relapse

Question 3

How do aminosalicylates work?

Answer 3

Block leucotriene and prostaglandin formation, therefore blocking transcription of inflammatory cytokines

Question 4

Name an aminosalicylate

Answer 4

Sulfasalazine

Question 5

What are the side effects of aminosalicylates?

Answer 5

GIT disturbance
Hypersensitivity
Thrombocytopaenia

Question 6

How do corticosteroids work?

Answer 6

Inhibit CK production

Question 7

Name a corticosteroid

Answer 7

Prednisolone

Question 8

Name a side effect of corticosteriods

Answer 8

Osteoporosis

Can cause dependency

Question 9

When are immunosuppressive agents indicated?

Answer 9

Long term maintenance if disease does not respond to aminosalicylates or steroids

Question 10

How do the immunosuppressive agents used in IBD work?

Answer 10

Purine analogues which inhibit nucleic acid synthesis

Question 11

Name 3 immunosuppressive agents given in IBD

Answer 11

Azathioprine
Mercaptopurine
Methotrexate

Question 12

What are the contraindications for mercaptopurine?

Answer 12

Not given in pregnancy

Cause bone marrow suppression

Question 13

What are antimicrobials used for in IBD?

Answer 13

Only for secondary complications

Question 14

What are biological treatments for IBD?

Answer 14

TNFa inhibitors: monoclonal antibodies against TNF

Question 15

Name an anti-TNF

Answer 15

Infliximab

Question 16

What 3 methods are used by laxatives?

Answer 16

Retain water and electrolytes in lumen
Reduce mucosal absorption
Increase intestinal motility

Question 17

What are the side effects of bulk forming agents?

Answer 17

Reduce drug absorption

Can cause intestinal and oesophageal obstruction if patient is not taking in enough water

Question 18

How do osmotic laxatives work?

Answer 18

Hold water in lumen by increasing the osmotic pressure of stool

Question 19

Give some examples of osmotic laxatives

Answer 19

Magnesium sulphate or hydroxide
Sodium (bis) phosphate
Lactulose

Question 20

Which patient groups should you take care in prescribing osmotic laxatives to?

Answer 20

Children

Renal impairment

Question 21

How do contact/stimulating laxatives work?

Answer 21

Stimulate myenteric plexus and mucosa to change muscle tone

This decreases the permeability of the mucosa

Question 22

Name 2 contact laxatives

Answer 22

Senna

Bisacodyl

Question 23

What form is Bisacodyl given in?

Answer 23

Suppository

Useful in those with difficulty swallowing

Question 24

Give 2 types of constipating agents

Answer 24

Absorbent compounds

Opiates

Question 25

Name 2 absorbent compounds

Answer 25

Pectin

Aluminium hydroxide

Question 26

How do opiates act as constipating agents?

Answer 26

Increase muscle tone and decrease propulsive movements

Question 27

Name an opiate constipating agent

Answer 27

Imodium