Gi_Maloney: Laxatives/antidiarrheals

Front 1

Name a bulk-forming laxative

Back 1

Methylcellulose

**FIBER**

Front 2

**Bulk Forming Laxative**

MOA of Methylcellulose

Back 2

Fiber absorbs water and causes Mechanical distension
↓
Peristalsis

Front 3

What may happen if you take
most fiber laxatives without water?

Back 3

It could expand in the esophagus causing obstruction

-TAKE WITH WATER TO PREVENT BOWEL OR ESOPHAGEAL OBSTRUCTION

Front 4

TAKE WITH WATER TO PREVENT BOWEL OR ESOPHAGEAL OBSTRUCTION

Back 4

Methylcellulose

(Bulk Forming Laxative)

Front 5

Adverse effects:

-Flatulence

-Bloating

Back 5

Methylcellulose

(Bulk Forming Laxative)

Front 6

1st Line for acute or chronic constipation

-works in 12-24 hr

Back 6

Methylcellulose
(Bulk Forming Laxative)

Front 7

A 55-year-old male is scheduled
for a colonoscopy. Would you
use methylcellulose as part of
their bowel prep?

Back 7

NO

You want to completely clear the colon and methylcellulose takes too long to get to the colon

Front 8

Name the Osmotic Laxative that is also given as an enema

Back 8

Sodium phosphate

Front 9

This osmotic laxative is a sugar

Back 9

Lactulose

Front 10

These two Osmotic Laxatives are nondigestible sugars or alcohols

Back 10

Lactulose

Polyethylene Glycol (PEG)

Front 11

Name the Osmotic Laxatives

Back 11

Sodium Phosphate
Lactulose
Polyethylene Glycol

Front 12

MOA:

Increased osmotic effect increases intraluminal volume and mass

Increased mass causes mechanical distension
↓
Peristalsis

Back 12

Osmotic Laxatives:
-Sodium Phosphate
-Lactulose
-Polyethylene Glycol

Front 13

How quickly does a sodium
phosphate enema work?

Back 13

Very quickly: 2-15 min

Front 14

This drug, if taken orally for bowel prep can cause ACUTE PHOSPHATE NEPHROPATHY (Ca-P precipitate in renal tubules)

-Patients need to drink 64oz of water when taking this drug!

*********

Back 14

Sodium Phosphate

Front 15

Calcium-Phosphate precipitate in kidney tubules

***

Back 15

***ACUTE PHOSPHATE NEPHROPATHY ***

Oral Sodium Phosphate and not enough water!!

Front 16

Lactulose is metabolized by
colonic bacteria. How quickly
will it work? Can you use it for bowel prep?

Back 16

SLOWLY: 24-48 hours

Can't use for Bowel Prep

Front 17

What would be the main side
effect of lactulose?

Back 17

Flatus and Cramps

Front 18

How quickly will low dose PEG
work when used for constipation?

How quickly will high dose PEG
work when used for constipation?

Back 18

low dose = slow: 1-3 days

high dose = fast: 1-2 hr

Front 19

Why are electrolytes added to
PEG when used in high dose
to evacuate the bowel?

Back 19

you don't want an electrolyte imbalance

Front 20

Name the stimulant laxative

Back 20

Bisacodyl

Front 21

MOA:

-Irritation → Enteric NS → Peristalsis

-↑water and electrolytes →Peristalsis

Back 21

Bisacodyl

Front 22

Used for Acute or chronic constipation

-Work in about 8-10 hours

Back 22

Bisacodyl

Bisacodyl can be used with PEG for bowel prep

Front 23

How do stool softeners work?

Back 23

**Docusate sodium**

Anionic surfactants that lower the fecal
surface tension in vitro, allowing water and lipid penetration

Front 24

Major use is to avoid straining during
defecation

Back 24

**Docusate sodium**
(Stool Softener)

Front 25

- Selective type 2 chloride channel (ClC-2) activator

- Increases intestinal fluid secretion and motility

-PRESCRIPTION DRUG FOR CHRONIC CONSTIPATION

Back 25

Lubiprostone

Front 26

MOA: Lubiprostone?

Back 26

Selective type 2 chloride channel (ClC-2) activator

Cl- goes in, water and Na+ follow

Front 27

Used for:
- Chronic constipation

-Constipation predominant irritable bowel syndrome

Back 27

Lubiprostone

Front 28

A 55-year-old female wants to try a colon cleanse to help her get rid of the toxins in her GI tract and to lose weight.

She has a history of hypertension, stable angina, type 2 diabetes, diabetic retinopathy, diabetic nephropathy. She gets some product from her neighbor, who says that it works really well – within just a few hours. While it worked like a champ, a few days later she started complaining of lethargy, swelling in her ankles, and she hasn’t been urinating very much. The agent that was most likely in the colon cleanse was:

A. Lactulose
B. Methylcellulose
C. Lubiprostone
D. Sodium phosphate
E. Polyethylene glycol (PEG)

Back 28

D. Sodium phosphate

**Acute Phosphate Nephropathy**

(Note: Both PEG and Sodium Phosphate are used for bowel prep!!)

Front 29

Name the Opiod Antidiarrheals

Back 29

Diphenoxylate + Atropine

Loperamide

Front 30

Diphenoxylate + Atropine - Crosses BBB/ Doesn't Cross

Loperamide- Crosses BBB/ Doesn't Cross

Back 30

Diphenoxylate + Atropine - Crosses BBB

Loperamide - doesn't cross BBB

Front 31

Why is atropine a
component of Lomotil (Diphenoxylate + Atropine)?

Back 31

Atropine side effects kick in if opiod abuse is occuring... Makes abuser feel like shit

Front 32

Opiod MOA:

Back 32

Hit mu and delta receptors in ENS
↓
Reduce propulsive peristalsis
Reduce intestinal secretions
↓
End Result:
Prolonged transit time and increased fecal viscosity

Front 33

Adverse Effects:

Drowsiness
Dizziness
Abdominal cramps
Constipation

Back 33

Opiods:
-Diphenoxylate + Atropine
-Loperamide

Front 34

OTC Antidiarrheal

-AKA: Pepto-bismol, Kaopectate

Back 34

Bismuth Subsalicylate

Front 35

MOA of Bismuth + Salicylate in Bismuth Subsalicylate OTC antidiarrheal

Back 35

**Bismuth**
↓
Antimicrobial/binds enterotoxins
↓
PREVENT TRAVELER'S DIARRHEA

**Salicylate**
↓
↓PG production
↓
↓Intestinal Secretions

Front 36

How effective is bismuth
subsalicylate in treating diarrhea?

Back 36

OK, but not as good as Loperamide!!

Front 37

This syndrome is characterized by chronic abdominal pain and altered bowel habits in the absence of an organic cause

Back 37

IBS

Front 38

Whats the best drug for treating IBS with constipation when other drugs fail?

Back 38

Lubiprostone (Rx)

Front 39

IBS Tx:

Constipation→ ?

Diarrhea → ?

Pain→ ?

Back 39

Constipation→ OTC laxatives

Diarrhea → Loperamide

Pain→ Anticholinergics, Antidepressants (SSRIs)