Pharmacology: Block 5: Gi Drugs

Front 1

Antacids

Back 1

Neutralize acid:

CaCO3 + 2H+ --> Ca2+ + CO2 + H2O

Calcium carbonate
Magnesium hydroxide
Aluminum-magnesium hydroxide

AE: pH of plasma up --> hypercalcemia --> Milk-alkali syndrome
Osmotic diarrhea with Mg salts

Front 2

Name four H2 blockers and their AEs

Back 2

Cimetidine (Tagamet)
Ranitidine (Zantac)
Famotidine (Pepcid)
Nizatidine (Axid)

AE: thrombocytopenia, drug-drug interactions (very rare, quite safe drugs).

Not as good as PPIs.

Front 3

Name six proton pump inhibitors

Back 3

Omeprazole
Esomeprazole
Pantopraszole
Rabeprazole
Lansoprazole
Dexlansoprazole

Front 4

PPIs: half-life, activation

Back 4

Short half-life but long duration of action. Acid activated, better to take 30 minutes before meals

Front 5

PPIs: AE

Back 5

Possible drug-drug interaction with clopidogrel.

Pneumonia, diarrhea (because of increased risk of infection)

Fe, Ca

Bone loss (from uncontrolled, observational studies), PPIs can affect intestinal absorption of Ca

Traveller's diarrhea is more common in those that take PPIs (because of higher stomach pH). Reduce acid = increase risk of infection.

Front 6

What goes up when histamine, PGE2, ACh, and Gastrin go up?

Back 6

Stomach acid secretion

Front 7

Name 2 cytoprotective agents

Back 7

Misoprostol
Sucralfate

Rendered irrelevant by effectiveness of PPIs

Front 8

Misoprostol

Back 8

PGE2 analog
Approved to prevent peptic ulcer disease with NSAIDs
AE: Nausea, diarrhea (prostaglandin effects)
Off label use: to stimulate uterine contractions

Front 9

Sucralfate

Back 9

Approved to treat peptic ulcer disease
Now used for misc. esophago-gastritides (non-acid reflux gastritis)
Well tolerated
Can have some drug-drug interactions

Front 10

Metaclopramide

Back 10

5-HT4 agonist
D2 antagonist (can cause dystonia)

Stimulates antral contractions, gastric emptying, mild increase in LES pressure

Renally cleared

AT: Has extrapyramidal effects:
Dystonia
Tardive dyskinesia (irreversible facial twitches)
Can be worse when stopped

Used as an adjunct for treatment of GERD

Front 11

Octreotide

Back 11

Somatostatin analogue

Decreases foregut secretions.

Improves secretory diarrhea mediated by hormones (such as VIP, gastrin)

Used with administration of CPT11 (irinotecan) to prevent diarrhea.

Used to treat (?) portal HTN

AE: decreases splanchnic blood flow, can cause bleeding with portal HTN, intestinal ischemia.

Bradycardia
Gallstones (because of decreased gallbladder emptying)

Front 12

VIPoma causes what?

Back 12

"secretory" diarrhea

Front 13

What are some of the things that comprise the diagnosis of IBS?

Back 13

Rome 3:

12 weeks of symptoms
Abdominal pain
Change in stool
Relieved by defecation
ABSCENCE of red flags (if there are red flags, it is not IBS)

IBS often happens after infections.

Front 14

Alosetron

Back 14

5-HT3 antagonist (seratonin)
Can cause ischemic colitis
Can cause severa constipation

Only approved in women! (More women are affected by IBS than men)

Front 15

What are three antispasmotics used for IBS and GI hypermotility? Tell me about them

Back 15

Dicyclomine, hyoscyamine

These are like atropine and scopolamine. They are antimuscarinic and have expected anticholinergic side effects. They help with spasm/pain.

Front 16

Name four antidiarrheals

Back 16

Loperamide
Diphenoxylate/atropine
Tincture of opium
Bismuth

Front 17

Loperamide

Back 17

(Imodium), antidiarrheal

Opiod agonist (all opiod agonists decrease intestinal motility)
No CNS penetrance so not addictive
Can cause thermoregulation issues (people who get runner's diarrhea cannot take loperamide)

Front 18

Diphenoxylate/atropine

Back 18

(Lomotil), antidiarrheal

CNS penetrance
Abuse potential

Front 19

Tincture of opium

Back 19

(Laudanum), antidiarrheal

CNS penetrance

Front 20

Bismuth

Back 20

Increases depolarization thresholds
Renal clearance

Can cause black stool ("pseudomelena") --> can be mistaken for an upper GI hemorrhage!

Aspirin + pepto bismol --> salicylate overdose!

Front 21

Psyllium

Back 21

Bulk-forming cathartic

Front 22

Lactulose

Back 22

Non-absorbed, non-digested disaccharide

Very sweet.

Fermentation in gut can cause bloating and flatulence.

Can be used to treat liver encephalopathy. Liver toxins get drawn into gut and get excreted.

Front 23

Polyethylene glycol

Back 23

Osmotic diuretic

Very well studied

Front 24

NA3PO4

Back 24

Excellent laxative, but can cause hypophosphatemia and renal failure.

No "ceiling", dehydration is a concern.

Still can be found in fleet enemas

Front 25

Bisacodyl

Back 25

Stimulant, cathartic (laxative) drug

Front 26

Senna

Back 26

(Senekot), stimulant laxative.

AE:
Melanosis
Carthartic colon
Dehydration/electrolytes
Some evidence that if you take it chronically you can cause damage to the enteric NS.

Front 27

Lubiprostone

Back 27

(Amitiza) Used for idiopathic chronic constipation

Front 28

Neostigmine

Back 28

(Prostigmin, Vagostigmin)

Used for ileus, Ogilvie's Syndrome (acute psuedoobstruction and dilation of the colon in the absence of any mechanical obstruction in severely ill patients).

AE: bradycardia

Front 29

c/c fiber and bran: effect on constipation

Back 29

Bran doesn't work!

Front 30

Docusate/Colace

Back 30

Often used as a laxative, but there is no supporting data!

Front 31

Pancrelipase

Back 31

Used for exocrine pancrease insufficiency

Some FDA approved, some not.
Varying concentrations of enzymes
Mainly differ in delivery systems
Very high doses associated with colonic strictures
Peds: if give too much pancrelipase to children, you can get strictures of the R colon.

Front 32

Ursodiol

Back 32

Stimulates bile salt-dependant bile flow.

Front 33

Cholestyramine

Back 33

Bile acid binding resin

Front 34

What demographic can be hypermetabolizers of omeprazole?

Back 34

15-20% of Asians

Front 35

If see fatigue, SOB, don't forget what in DDx?

Back 35

Anemia

Front 36

LUQ pain, relieved by defecation. What could be the diagnosis?

Back 36

IBS

Front 37

What herbal remedy is ok to use for IBS?

Back 37

peppermint oil

Front 38

What is the proper workup for constipation?

Back 38

Check red flags (R/O obstructive lesion) --> look at meds list for things that could be causing constipation (codine, anticholinesterases) --> fiber --> osmotic laxative --> if still have sx --> more aggressive workup

Front 39

What can you give to decrease the necessary dose of azthioprine?

Back 39

allopurinol