Pharm: Laxatives & Anti-Diarrheal Agents

Question 1

What is an osmotic laxative?

Answer 1

Nonabsorbable substances that draw water into the intestinal lumen leading to distention leading to peristalsis

Question 2

What are the two main magnesium-containing diuretics?

Answer 2

1. magnesium citrate
2. magnesium hydroxide (Milk of Magnesia)

(Think of the Mg2+ magnets used to massage surfer dude)

Question 3

___________ is often used in pre-op settings to clean out the colon.

Answer 3

PEG (polyethylene glycol)

Think of the wooden “peg” uncapping the drain letting the bubble bath water to flow out

Question 4

What is PEG?

Answer 4

An osmotic laxative- an nonabsorbable sugar

Question 5

How does lactulose work?

Answer 5

Colonic bacteria metabolize lactulose into acid, lowering colon pH, converting NH3 to NH4+, trapping it in the lumen for excretion (think of the pH meter on the fish tank)

Question 6

What are two non absorbable sugars?

Answer 6

1. PEG

2. lactulose

Question 7

What are two triggers of hepatic encephalopathy?

Answer 7

1. Colonic bacteria making NH3

2. Eating too much protein

Question 8

__________ is used in killing bacteria that generate NH3 in hepatic encephalopathy.

Answer 8

Rifaximin (think of the Rifaximin Fisherman)

Question 9

What are three types of laxatives?

Answer 9

1. osmotic
2. bulk-forming
3. surfactant agents (stool softeners)
4. stimulant (cathartics)

Question 10

Two bulk-forming laxatives are ________ and __________.

Answer 10

methylcellulose and psyllium- both are large molecules that are unabsorbed by the GI tract. They can also absorb large amounts of water (think of the bulky seaweed pile)

Question 11

How does docusate work?

Answer 11

It is a surfactant agent that facilitates water penetration into the stool (think of the water-logged canoe at the DOCK)

Question 12

Chronic use of _________ can lead to characteristic darkening of the colon.

Answer 12

senna - effect is called melanosis coli - stimulates enteric nervous system (think of the senna sun tan being rubbed vigorously onto abs)

Question 13

What are two contraindications of antidiarrheal use?

Answer 13

1. bloody diarrhea (bloody stool OUTSIDE the massage parlor)

2. fever (inflammatory candles OUTSIDE the massage parlor)

Question 14

What does stimulation of the mu-opioid receptors do?

Answer 14

It increases segmentation (NOT peristalsis), thus increases transit time.

Question 15

What are two examples of antidiarrheal agents?

Answer 15

1. mu-opioid agonists (think mu-ssage)

2. octreotide

Question 16

True or false: opioid-based antidiarrheals cannot cross the blood-brain barrier.

Answer 16

Loperamide cannot, but diphenoxylate can (therefore given with atropine)

Question 17

What are two examples of mu-opioid agonists that are used as antidiarrheals?

Answer 17

1. loperamide (think of the lop-eared rabbit)

2. diphenoxylate (think of the diphenoxylate dolphins)

Question 18

Somatostatin analogs like octreotide can be used to treat the secretory diarrhea found in __________ and ____________.

Answer 18

VIPomas and carcinoid syndrome

think of the cancer crab sign saying VIP Only holding a STOP sign

Question 19

Carcinoid syndrome/tumors is usually characterized by _______________ (location and secretion).

Answer 19

Ileal tumor with hepatic metastasis that secretes active hormones/NT like 5HT

Question 20

What is a VIPoma?

Answer 20

Pancreatic endocrine tumor that secretes vasoactive intestinal peptide (VIP)