GI drugs II

Question 1

MOA of the “Setron”s such as Ondansetron (Zofran)

Answer 1

• 5HT3 antagonists

Question 2

Use of Ondansetron (Zofran)

Answer 2

• nausea and vomiting induced by chemotherapy, radiation, gastric diseases
  
  • NOT for motion sickness

Question 3

MOA of Prochlorperazine

Answer 3

• block DA, muscarinic, and histamine receptors

Question 4

MOA of Promethazine

Answer 4

• block DA, muscarinic, and histamine receptors

Question 5

use for Promethazine and Prochlorperazine

Answer 5

• highly sedating, post-op antinausea
• will work for motion sickness, not DOC

Question 6

MOA and use of of Dronabinol

Answer 6

• cannabinoid
• used for chemo-induced N/V
• stimulates appetite

Question 7

List the 5 types of laxatives

Answer 7

1. bulk-forming: mild
2. osmotic: intense
3. mucosal agents: irritant
4. lubricating agents
5. stool softeners

Question 8

Explain the bulk forming laxative

Answer 8

• high fiber
• take with plenty of water
• bloating and flatulence common

Question 9

List the bulk forming laxatives

Answer 9

• Psyllium (Metamucil®)

Question 10

List the types of osmotic laxatives

Answer 10

• Magnesium hydroxide
• Sodium salts: oral or enema

Question 11

MOA of Polyethylene glycol

Answer 11

• laxative
• insoluble, holds water in intestine

Question 12

Use of Polyethylene glycol

Answer 12

• prep for colonoscopy: large volume consumed
• Miralax: OTC for occasional constipation, use for up to 7 days

Question 13

MOA and Use of Lactulose

Answer 13

• used in cirrhosis and liver disease to decrease blood ammonia levels
• anion trap of NH3 when it enters the GI lumen and converts it to NH4 (becomes trapped)
• causes diarrhea

Question 14

MOA of mucosal agents

Answer 14

• stimulate peristalsis
• enhance secretion/inhibit absorption H20

Question 15

List the mild mucosal agent

Answer 15

Senna (Senokot®)

Question 16

MOA of Docusate sodium

Answer 16

• lubricant
• emulsifies, softens feces

Question 17

MOA of Lubiprostone (Amitiza®)

Answer 17

• prostaglandin E1 analogue
• increases fluid secretion -> softens stool
  
  • no laxative dependence : can use long term

Question 18

contraindications to using laxatives

Answer 18

• N/V
• abd cramps
• undiagnosed abd pain
• appendicitis
• intestinal obstruction

Question 19

MOA of Loperamide

Answer 19

• opioid used for diarrhea
• doe not enter CNS, low abuse

Question 20

MOA of Diphenoxylate/atropine

Answer 20

• opioid with atropine used for diarrhea
  
  • reduces abuse potential, increases effectiveness
  • atropine decreases GI spasms
• anticholinergic side effects

Question 21

contraindications to use opioids for diarrhea

Answer 21

• infections
  
  • dec expulsion of pathogen
• ulcerative colitis
  
  • toxic megacolon
• recovering drug addicts
  
  • some abuse potential with diphenoxylate

Question 22

MOA of bismuth subsalicylate (pepto bismol)

Answer 22

• absorbs water and pathogens
• used for traveller’s diarrhea
• side effects: black tongue

Question 23

MOA of Simethicone (Gas-X)

Answer 23

• coats gas, dissipates
• decreases bloating, flatulence