GI V: motility and inflammatory bowel disease

Question 1

Drugs used to relieve constipation

Answer 1

1st line–> Bulk laxatives (methylcellulose)
2nd line –> osmostic laxatives (Mg hydroxide, Sodium citrate)
3rd line –> Stimulant laxatives (Senna)

Question 2

Osmotic laxatives Examples

Answer 2

Mg Sulfate
Mg hydroxide
Sodium citrate
Sodium Phosphate
Lactulose
Macrogols

Question 3

MoA of Osmotic laxatives

Answer 3

Provides osmotic load to draw water into GI lumen –> traps increased volumes of fluid in the lumen of the bowel –> accelerate the transfer of the gut contents through the small intestine.
* Distension in colon and purgation within 1h

Question 4

Clinical uses of Magensium sulfate/ Mg hydroxide

Answer 4

2nd line tx of constipation
they are Saline purgatives→ poorly absorbed
solutes. Mg absorbed is too small to have adverse effects

Question 5

AE of Osmotic laxatives

Answer 5

1) Heart block,
2) neuromuscular block or CNS depression.
3) Abdominal cramps.

Question 6

Contraindication of Osmotic laxatives

Answer 6

In Small kids and
poor renal function

Question 7

Bulk laxatives Examples

Answer 7

Methylcellulose
Sterculia
Agar
Bran
Ispaghula husk
Psyllium

Question 8

Clinical uses of Methylcellulose and Psyllium

Answer 8

1st line anti-constipation drugs
* May take a few days to work
* slow-acting

* Bulk laxatives

Question 9

AE of Bulk laxatives

Answer 9

Bloating

* no serious AE

Question 10

MoA of Bulk laxatives

Answer 10

soluble fibers that draw water into gut lumen, forming viscous liquid (bulky hydrated mass) that promotes peristalsis

Question 11

Clinical uses of Lactulose

Answer 11

1) Relives constipation
2) tx of hepatic encephalopathy

Question 12

AE of Lactulose

Answer 12

1) Flatulence (“passing wind”),
2) cramps,
3) diarrhoea,
4) electrolyte disturbance.

Question 13

Stimulant laxatives examples

Answer 13

Bisacodyl
Glycerol
Senna
Dantron

*Great Bella Sees Delusions

Question 14

MoA of Senna/ Bisacodyl

Answer 14

Enteric nerve stimulation –> colonic contraction (increases peristalsis)

* Stimulant laxatives

Question 15

Clinical uses of Senna/ Bisacodyl

Answer 15

3rd line anti-constipation tx

* Stimulant laxatives

Question 16

AE of Stimulant laxatives

Answer 16

1) Abdominal cramps and
2) melanosis coli - caused by lon-term tx esp. Senna (deposition of brown/black pigment in the colorectal mucosa)

Question 17

Stool softener examples

Answer 17

Docusate sodium
Arachis oil
Liquid paraffin

Question 18

why are laxatives preferred over stool softeners in the tx of Constipation?

Answer 18

laxatives increase motility in the GI tract unlike stool softners, which only soften stool

Question 19

D2 receptor antagonists (Prokinetic) used in the tx of constipation

Answer 19

Metoclopramide
Domperidone

Question 20

Clinical uses of Metoclopramide and
Domperidone

Answer 20

1) GOERD
2) Gastroparesis (paralysis of the stomach -> slows digestion)
3) Anti-emesis

* D2 receptor antagonists

Question 21

MoA of Metoclopramide
Domperidone

Answer 21

D2 receptor antagonists –> increases motility in the lower oesophageal sphincter and duodenum

Question 22

4th line tx of constipation?

Answer 22

Prucalopride - selective HT-4 receptor agonist (prokinetic)

Question 23

AE of Prucalopride

Answer 23

Ab cramps,less appetite, diarrhoea, dizziness, dyspepsia, fatigue, flatulence, headache, nausea, polyuria, rectal bleeding, vomiting

Question 24

Anti-diarrheal agents?

Answer 24

1) Opiates (Codeine, Loperamide)
2) Anti-cholinergics (Atropine, Hyoscine)

Question 25

Which Opiate is more preferred in the tx of diarrhea, Codein or Loperamide . Explain

Answer 25

Loperamide –> not Addictive

Codeine acts on the CNS unlike Loperamide which acts on the PNS, meaning that it does not cross the BBB and therefor is not addictive like Codeine

• Codeine is addictive if used for > 7 days

Question 26

AE of Opiates

*Codeine, Loperamide

Answer 26

1) Sedation
2) Dizziness
3) dry mouth
4) nausea
5) Constipation
6) Vomiting
7) ab cramps
8) mioses ( pupil constriction- “pin-point pupil)

Question 27

AE of anti-cholinergics (muscarinics)

*Hyoscine , Atropine

Answer 27

1) Mydriasis (pupil dilation )
2) Dry mouth
3) blurred vission
4) urinary retetion
5) constipation
6) Tachycardia

Question 28

Drugs used in the tx of inflamatory bowel disease (IBD)

Answer 28

1) Glucocorticoids (Prednison) –> Chron’s
2) Aminocalycilate (Sulfasalazine)–> Ulcerative colitis

Question 29

clinical uses of Methotrexate and Azathioprine

Answer 29

Long-term managment of IBD (reduce the long-term need for steroids)

Question 30

MoA of Azathioprine and 6-mercapto-purine

Answer 30

Inhibits Purine synthesis –> reduces inflammation

Question 31

1st line tx of Chron’s disease

Answer 31

Glucocortcoids
Prednisone/ Budesonide

* reduce inflammation

Question 32

1st line tx of Ulcerative colitis

Answer 32

Aminosalicylates (5-ASAS)
1) Sulfasalazine
2) Olsalazine
3) Balsalazide

-salazin/d

Question 33

CU of Sulfasalazine

* 5-ASA

Answer 33

Ulcerative colitis

Question 34

AE of Sulfasalazine

Answer 34

1) Diarrhoea,
2) salicylate sensitivity,
3) interstitial nephritis (monitor kidney
function - GFR),
4) decreases number and motility of sperm (reversible)

Question 35

Alternative drugs used in the tx of IBD when pateints are unresponsive to other treatments (steroids/ 5-ASAs)

Answer 35

Infliximab/Adalimumab
(TNF-a inhibitors)