Wk4 antidiarrheals/laxatives/IBS drugs Flashcards Preview

GI > Wk4 antidiarrheals/laxatives/IBS drugs > Flashcards

Flashcards in Wk4 antidiarrheals/laxatives/IBS drugs Deck (34):
1

Cisapride

Prokinetic --> increased motility

5HT4 agonist (and 5H3 ANtagonist)

Tx: diabetic gastroparesis

**restricted use dt cardiac toxicity

2

Domperidone

D2 receptor antagonist

increase GI motility throughout the entire GI tract

3

Macrolides (erythromycin)

stimulate motilin receptors directly on GI smooth muscle → initiation of migrating motor complex

4

Metoclopramide

D2 receptor antagonist

increase GI motility throughout the entire GI tract

5

Diphenoxylate

Opiate

most effective antidiarrheal

Crosses BBB so abuse potential and needs Rx

mixed with atropine to discourage abuse

6

Loperamide

opiate

most effective antidiarrheal

doesn't cross BBB so available OTC

7

Cholestyramine

Binds bile salts

8

Colestipol

Binds bile salts

9

Kaolin/Pectin

Absorbant

10

Bismuth Subsalicylate

MOA as antidiarrheal?

inhibits prostaglandin and chloride secretion in the large intestine

11

Crofelmer use?

MOA?

HIV diarrhea

blocks CFTR --> decreases Cl- secretion

12

Octreotide MOA?

Effects at different doses?

Somatostatin analogue

low dose stimulates motility

high dose inhibits motility

overall decrease in secretion

13

Docusate class?

MOA?

Stool softener

surfactant --> softens stool by allowing mixing of aqueous and fatty substances

14

Mineral Oil Class?

MOA?

Stool softener

lubricates feces --> decreased water absorption from stool

15

Dietary fiber

increase mass of stool → distension → enteric reflexes → increased GI motility → decreased transit time through the colon

"stool stabilizers" -- also less diarrhea

16

Anthraquinone

Contact cathartic

Stimulates peristalsis

large intestine

less potent

17

Bisacodyl

Contact cathartic

Stimulates peristalsis

large intestine

less potent

is given as a prodrug → 6 hour latency

18

Castor oil

Contact cathartic

Stimulates peristalsis

large AND small intestine

VERY potent

**uterine contractions

dehydration

19

Linaclotide

activates guanylyl cyclase-C on the luminal surface of intestinal epithelial cells

increased intra- and extra-cellular cGMP activates (CFTR) → increased Cl- secretion

Tx: constipation IBS

not in pregnancy or for peds

20

Lubiprostone

activation of chloride channel ClC-2 → more Cl- secretion → increased water content in stool

constipation IBS

NOT in PREGNANCY

21

Alvimopan

selective μ receptor antagonists that do not cross the BBB (won't antagonize central analgesic effects of opiate medications)

used to shorten period of postoperative ileus following small or large bowel resection (short term)

**cardiotoxicity

22

Methylnaltrexone

selective μ receptor antagonists that do not cross the BBB (won't antagonize central analgesic effects of opiate medications)

patients receiving palliative care for advanced illness (long term)

23

Lactulose

Osmotic cathartic (purgative)

reduces plasma NH4 conc; tx for hepatic encephalopathy

24

Magnesium hydroxide

Osmotic cathartic (purgative)

MOA???

25

Sodium Phosphate

Osmotic cathartic (purgative)

MOA: increased electrolytes in colon

26

Polyethylene glycol

Osmotic cathartic (purgative)

used for whole bowel irrigation prior to colonoscopy/endoscopy

27

TCA's

Amitriptyline, Desipramine

blocking NE reptake into postganglionic sympathetic neurons results in increased NE concentrations in the synapse → increased NE actions on the α2 receptor → decreased ACh release

blocking DA reuptake into enteric interneurons → increased DA concentrations in the synapse → increased D2-mediated inhibition of cholinergic smooth muscle motoneurons

Diarrhea IBS tx

28

SSRIs

Fluoxetine, Paroxetine, Sertraline

Increased peristalsis

more 5HT in synapse --> afferent activation

Tx: constipation IBS

29

Alosterone

Antidiarrheal

5HT3 antagonist

Tx: diarrheal IBD

**last resort, bad constipation

30

Tegaserod

Prokinetic

selective 5HT4 agonist

Tx: constipation IBS

**last resort, big Cardiac side fx

31

cause a characteristic, harmless, brown pigmentation of the colonic mucosa

anthraquinones

32

D2 receptor antagonist

does not cross BBB

compassionate use only

not available in USA

Domperidone

33

D2 receptor antagonist

crosses BBB

parkisonism

pituitary effects (impotence, galactorhea, menstruation disorders)

Metaclopramide

34

Secondary MOA or tegaserod and cisapride:

activate cAMP-dependent chloride secretion form the colon