GastroIntestinal III

Question 1

What is a laxative? What is another name for them

Answer 1

Excretion of soft but formed stool

Aperients

Question 2

What are cathartics? What is another name for them

Answer 2

Produces a more fluid evacuation.

Purgatives

Question 3

Cathartics enhance transit of intestinal contents by cathartics due to….? (2)

Answer 3

Stimulation of local intrinsic myenteric reflexes within visceral sm m

Stimulation of cholinergic receptors of the extrinsic parasympathetic nervous system

Question 4

What are the 5 classifications of laxative and cathartics?

Answer 4

Emollient lax
Bulk-forming lax

Saline purgs
Irritant cath
Neuromuscular purgs

Question 5

3 characteristics of Emollient laxatives?

Answer 5

Acts unchanged

not absorbed

softens and lubricates the fecal mass which leads to defecation

Question 6

What are the 3 emollient laxatives?

Answer 6

Mineral oil

Docusate sodium

White soft paraffin

Question 7

What is the clinical use for White soft paraffin?

Answer 7

Hair ball removal in cats.

Cat-Lax

can also be used as a preventative

Question 8

How does docusate sodium work?

Answer 8

It is an anion surface active agent

aka, reduces surface tension

Question 9

When would you use docusate sodium?

Answer 9

Constipation of small animals

Colon impaction in horses

Question 10

What else is docusate sodium used for?

Answer 10

Ear wax removal–Waxsol

Question 11

how long does it take for maximal fecal softening when using docusate sodium?

Answer 11

3 days

Question 12

What is a commonly used laxative?

Answer 12

Mineral oil

Question 13

What two emollient laxatives can you not use together? why?

Answer 13

Mineral oil and docusate sodium.

Docusate will emulsify the mineral oil which will lead to absorption of oil!!!

Question 14

What will happen if you accidentally administer mineral oil into the trachea?

Answer 14

Lipid pneumonitis

Question 15

What laxative will interfere with the healing of wound in the ano-rectal region through leakage?

Answer 15

mineral oil

Question 16

What kind of side effects should you think about when using mineral oil chronically?

Answer 16

may impair absorption of fat soluble vitamins, other nutrients, and co-admin of drugs

Question 17

What can happen to the intestinal wall and liver when using mineral oil?

Answer 17

granulomatous lesions

Question 18

What are your Bulk Forming Laxatives?

Answer 18

Methycellulose
Carboxymethylcellulos sodium
Plantago seed
Bran
Psyllium granules/powder

Question 19

MOA of bulk forming lax

Answer 19

Hydrophillic so they ABSORB water and swell to form an emollient gel.
This increases bulk in the small intestine and colon causing distention which will stimulate peristaltic activity

Question 20

How long does it take for bulk forming laxatives to kick in?

Answer 20

12-24 hrs

maximal effect occurs on day 2-3 of tx

Question 21

What are the different ways you can use Bran/wheat fibre?

Answer 21

Powder

Unprocessed to food

Mash-mainly for horses

Question 22

What is used for the tx of impactions caused by ingestion of sand?

Answer 22

Psyllium granules/powder

Question 23

How do saline purgatives work?

Answer 23

Retains or attracts water into the intestinal lumen by osmotic forces

Question 24

What do you want to remember when using saline purgatives?

Answer 24

Make sure the animal has plenty of water!!

Question 25

When would you NOT want to use saline purgs?

Answer 25

In a dehydrated animal

Question 26

How long does it take for saline purgs to work? Monogastric vs ruminants

Answer 26

Mono: 3-12 hrs Rum: after 18 hrs

Question 27

What are the 5 types of saline purgatives?

Answer 27

Magnesium sulphate (Epsom salt) Sodium sulphate Milk of magnesia Hypertonic solutions Lactulose

Question 28

How is Magnesium sulphate used and on who?

Answer 28

Increases CCK release-this increases peristalsis Cows

Question 29

What animal is sodium sulphate used in?

Answer 29

Horses

Question 30

When should you not use milk of magnesia on an animal?

Answer 30

impaired renal function absorbed magnesium ions will produce toxicity

Question 31

What are examples of hypertonic solutions?

Answer 31

Sugar alcohols Mannitol and Sorbitol

Question 32

Where does Lactulose work in the body?

Answer 32

Large Intestine

Question 33

MOA for lactulose

Answer 33

Microflora ferments lactulose to acetic/lactic/other organic acids. This lowers the pH of colonic contents which exerts and osmotic effect. The attracted water will soften the fecal mass and improves peristalsis

Question 34

What disease can you use lactulose for?

Answer 34

Hepatic encephalopathy

Question 35

What are your two stimulant cathartics?

Answer 35

Castor oil Anthraquinones

Question 36

MOA for Castor Oil

Answer 36

The oil is hydrolized by pancreatic lipases to glycerol and *ricinoleic acid* This is an irritant cathartic. It reduces the net absorption of fluid and electrolytes and stimulates intestinal peristalsis 1-2 sm an after 12 lg an

Question 37

MOA for anthraquinones

Answer 37

Undergoes hydrolysis by bacterial enzymes in the LI to release *aglycones*, this is a plant toxicity This stimulate myenteric plexus 6-12 hrs Sm An 12-36 in Lg An

Question 38

What happens to horses when repeating doses of anthraquinones?

Answer 38

Superpurgation

Question 39

In what scenario should you think about when antraquinones?

Answer 39

Nursing animals Can be excreted through milk

Question 40

What are your Neuromuscular purgs?

Answer 40

Cholinergic agents (neostigmine, physostigmine, bethanecol, carbachol) Vasopression Oxytocin PGF2a PG analogs

Question 41

How does cholinergic agents cause defacation?

Answer 41

Increases GIT motility

Question 42

When should you not use cholinergic agents for GI motility?

Answer 42

mechanical obstructions

Question 43

How do vasopressons, oxytocin, pgf2a, and pg analogs work for defecation?

Answer 43

Stimulates visceral sm m contractions