GI drugs

Question 1

Magnesium Sulfate

Answer 1

increases gastric motility causing DIARRHEA

Question 2

Aluminum Hydroxide

Answer 2

relaxes small muscle causing CONSTIPATION

Question 3

Antacids

Answer 3

inorganic base that neutralizes acid and forms salts
HIGH DRUG INTERACTIONS
Food prolongs effects, low systemic absorption

Question 4

Antacids decrease absorption of

Answer 4

iron, theophylline, isoniazide, quinolones, ketoconazole

Question 5

Antacids decrease bioavailability of

Answer 5

pheytoin, digitalis, propranolol

Question 6

Antacids increase elimination of

Answer 6

phenobarbital, salicylates

Question 7

H2 blockers

Answer 7

-tidine

Decrease NOCTURNAL acid formation, pre-op decrease in stomach acid, prevents stress ulcers

Question 8

SE of Cimetidine

Answer 8

INHIBITS CYP3A4
LOTS OF DRUG INTERACTIONS
warfarin, phenytoin, benzos, etc
Chronic high doses=anti androgen effects

Question 9

PPIs

Answer 9

-prazole
irreversibly bind and inhibit H-K-ATPase pump in the parietal cells of stomach
Prevent NSAID ulcers
PRODRUGS, plasma decreases but effect wears on (regardless of when taken)
FEW SE, but may need to supplement Ca2+

Question 10

Sucralfate

Answer 10

Cytoprotectant
Use: Ulcers
TAKE BEFORE MEAL with NO ANTACIDS
SE: Constipation

Question 11

Misoprostol

Answer 11

PG analogue cytoprotectant
Ulcer prevetion with NSAID use
CI IN PREGNANCY (used for abortion)

Question 12

Tritec

Answer 12

bismuth salicylate+metronidazole+tetracycline

Question 13

Helidac

Answer 13

Ranitidine+bismuch citrate+clarithromycin

Question 14

Bethanacol

Answer 14

Muscarinic agonist to increase GI tone and motility
POST-OP ILEUS AND INCREASE LES TONE!
SE: Cramping, muscarinic effects
NO CNS EFFECTS

Question 15

Metoclopramide (Reglan)

Answer 15

DA receptor antagonist to block ACh in GI to increase motility and tone in UGI
ANTIEMETIC
SE: Parkinson-like, EPS, depression, anxiety
METHYLGLOBINEMIA IN NEONATES
DON’T USE IN PGN!

Question 16

Erythromycin

Answer 16

DOC diabetic gastroparesis

Question 17

Glycopyrrolate

Dicyclomine

Answer 17

ANTISPASMODICS
Anti-muscarinics used to block vagal input
Decrease intestinal activity and cramping/spasms
SE: ANTICHOLINERGIC TOXIDROME

Question 18

Alosetron

Answer 18

DO NOT USE! Strictly regulated

Question 19

Amitriptyline

Answer 19

Anticholinergic effect
Use: IBS to decrease spasticity
SE: MANY!!

Question 20

-Setron

Ondansetron=Zofran

Answer 20

SELECTIVE 5-HT blocker to the CTZ and GI
ANTIEMETIC
Useful for everything but motion sickness n/v
SE: HA, constipation

Question 21

Promethazine (Phenergan)

Prochlorperazine (Compazine)

Answer 21

Block DA, muscarinic, and histamine receptors
Use: Post-op nausea, etc INCLUDING MOTION SICKNESS
SE: SEDATION (usually not a terrible thing)

Question 22

Dronabinol

Answer 22

THC compound

Anti-emetic

Question 23

Bulk fiber laxatives

Answer 23

increase bulk of feces– DRINK PLENTY OF WATER

SE: Flatulence; impaction and obstruction w/o adequate water

Question 24

Lactulose

Answer 24

Osmotic laxative

Ion trapping of ammonia (into ammonium in GI) to help decrease NH4 in cirrhosis patients

Question 25

Polyethylene glycol

Answer 25

GoLytely, Miralax PREP FOR COLONOSCOPY NG or oral

Question 26

Sorbitol | Mannitol

Answer 26

Not used anymore but overuse can cause diarrhea

Question 27

Senna

Answer 27

Irritant laxative, stimulate peristalsis to enhance secretion and absorption of water very mild

Question 28

Biscodyl

Answer 28

Irritant laxative | inhibits absorption of water and stimulates peristalsis

Question 29

Castor oil

Answer 29

irritant laxative | DON'T USE IN PGN- VERY INTENSE! Requires bile for excretion-- don't use with obstruction

Question 30

Mineral oil Docusate sodium Glycerin

Answer 30

Not very effective as laxatives, act more as stool softeners | Docusate sodium=emulsifying agent

Question 31

Lubiprostone

Answer 31

PG E1 derivative increases intestinal secretions to increase motility Stool softener, does not alter serum electrolytes DOES NOT PRODUCE TOLERANCE

Question 32

Sulfasalazine

Answer 32

DOES NOT WORK VIA COX, requires colonic bacterial activation | USED FOR UC

Question 33

Bulk forming laxatives

Answer 33

First line treatment for diarrhea

Question 34

Loperamide (imodium)

Answer 34

Opioid analogue to decrease peristalsis | OTC, no CNS effect so low abuse potential

Question 35

Diphenoxylate + Atropine (Lomotil)

Answer 35

Some CNS effect but decreased with atropine combo

Question 36

Bismuth subsalicylate (Pepto)

Answer 36

Traveler's diarrhea absorbs excess water, may absorb toxins and destroy pathogens-- salicylate may inhibit PG synthesis to decrease secretion and inflammation Produces BLACK STOOL (sometimes)

Question 37

Contraindications to opioid anti-diarrheal use:

Answer 37

1) due to organisms 2) UC 3) opioid abuse history