Chapter 6 GI agents - laxatives and cathartics

Question 1

plecanatide (trulance)

chronic idiopathic constipation drugs

Answer 1

• Guanylate cyclase C agonist
• induce cGMP in order to inc intestinal fluid

effect
* diarrhea
* dehydration in children

PO

Question 2

prucalopride (motegrity)

chronic idiopathic constipation drugs

Answer 2

• selective serotonin 4 reeptor agonist

effect
* abdominal pain
* diarrhea

Question 3

naldemedine (symproic)

opoid induced constipation drugs

Answer 3

• mu opioid antagonist

effect
* opiate withdrawal sx w/ pt w/ disrupted BBB

Question 4

psyllium (metamucil)

bulk forming

Answer 4

• nondigested plant cell wall ABSORBS h2o into feces => soften stool

effects
* impaction if bolus obstructed

takes 1-3 days

Question 5

saline solutions (milk of magnesia)

Answer 5

• Mg++ or Na+ salts are poorly absorbed and thus draw water into lumen ==> high dose rids of parasites + empties preoperatively

effects
* hypocalcemia
* exacerbate cardiac, renal or convulsive d/o

watery excretion within 1-3 hours

Question 6

bisacodyl (dulcolax)
senna (senokot)

stimulant laxatives and cathartics

Answer 6

• inc h2o and electrolytes into feces + inc intestinal motility

effect
* serious diarrhea

soften feces in 6-8 hours

Question 7

polyethylene glycol (miralax)

Answer 7

hyperosmolarity draws h2o into colon

effects
* cramps
* bloating

Question 8

glycerin

Answer 8

• hyperosmolarity draws h2o into colon

evacuates colon in 15 mins

Question 9

lactulose

Answer 9

hyperosmolarity draws water into colon (ammonia)

• cramps, n/v

Metabolized in intestine to lactate acts as a laxative osmotically and by lowering pH

Question 10

mineral oil

Answer 10

• lubricates feces + prevents loss of water from them

effect
* anal leakage
* reduce vitamin absorption
* aspiration pneumonitis w/ oral use
*

Question 11

docusate (colace)

Answer 11

• improves penetration of water + fat into feces
• diarrhea, cramps
• INC mineral oil absorption (NO MINIERAL OIL USE PLEASE)