GI Pharm from FA

Question 1

what class?

Cimetidine

Ranitidine

Famotidine

Nizatidine

Answer 1

H2 blockers

Take H2 blockers before you dine: “Table for 2”

Question 2

H2 blockers: mech?

Answer 2

Reversible block of histamine H2 receptors

-> decr H+ secr by parietal cells

Question 3

H2 blockers: use?

Answer 3

peptic ulcers, gastritis, mild esophageal reflux

Question 4

Which H2 blockers have the most toxicity?

what is that tox?

Answer 4

Cimetidine: inhibits cytochrome P-450 -> multiple drug interactions.

Also is an anti-androgen -> prolactin release, gynecomastia, impotence, decr libido in males

Crosses BBB -> confusion, dizziness, headaches

crosses placenta.

Both Cimetidine and Ranitidine decrease renal excr of creatinine (could be a reason for elevated creatinine without another cause)

Question 5

Name the H2 blockers that have no toxic effects listed in FA? (2)

Answer 5

Famotidine

Nizatidine

(Ranitidine has only one tox effect: decr renal excr of creatinine. Cimetidine has a boatload.)

Question 6

What class?

Omeprazole, Lansoprazole, Esomeprazole, Pantoprazole, Dexlansoprazole

Answer 6

Proton Pump Inhibitors

Question 7

Mechanism?

Omeprazole, Lansoprazole, Esomeprazole, Pantoprazole, Dexlansoprazole

Answer 7

Irreversibly inhibit H/K ATPase in stomach parietal cells

(receptors on LUMEN side of the stomach)

(Proton Pump Inhibitors: inhibit “primary active transport”)

Question 8

Clinical Use?

Omeprazole, Lansoprazole, Esomeprazole, Pantoprazole, Dexlansoprazole

Answer 8

Peptic ulcer, gastritis, esophageal reflux, Zollinger-Ellison syndrome

Question 9

Toxocity?

Omeprazole, Lansoprazole, Esomeprazole, Pantoprazole, Dexlansoprazole

Answer 9

Incr risk of C Diff infection

Pneumonia

With long term use: hip fractures, decr serum Mg2+

(I’m sure this all has something to do with acid.)

Question 10

Bismuth, Sucralfate: Mech?

Answer 10

Binds to ulcer base –> physical protection, allows Bicarb secretion to re-establish pH gradient in the mucous layer.

Question 11

Bismuth, Sucralfate: Use?

Answer 11

Allows ulcer healing

Traveler’s diarrhea

Question 12

Misoprostol

Mech?

Answer 12

PGE₁ analog

• Incr production/secretion of gastric mucous barrier
• Decr acid production

Question 13

Misoprostol

Use?

Answer 13

• Prevents peptic ulcers from NSAID use (NSAIDs block PGE₁ production)
• Maintains PDA
• Ripens cervix -> induces labor

(miso soup steams things open (PDA, cervix). Also is Jen’s hangover cure: aspirin + miso soup)

Question 14

Octreotide

Mech?

Answer 14

Long-acting somatostatin analog

Acts on ECL cell, not parietal cell

(Endocrine connection: somatostatin from hypothal decr GH and TSH release. If hypothalamus is destroyed, Octreotide can replace somatostatin)

Question 15

Octreotide

Use?

Answer 15

• Acute variceal bleeds
• Acromegaly (blocks GH release from pituitary)
• VIPoma
• carcinoid tumors
• helpful for ‘secretory’ diarrhea

Question 16

Octreotide

Tox?

Answer 16

nausea, cramps, steatorrhea

Question 17

What class?

Aluminum hydroxide

Calcium carbonate

Magnesium hydroxide

Answer 17

Antacids

Question 18

Antacids: general tox?

Answer 18

• affect absorption, bioavailability, or urinary excr of other drugs by altering gastric and urinary pH or by delaying gastric emptying
• Hypokalemia

Question 19

Aluminum hydroxide: tox?

Answer 19

Antacid general tox = alter gastric/urinary pH or delay gastric emptying -> affect other drugs; hypokalemia

Specific to Al hydroxide: constipation, hypophosphatemia, prox muscle weakness, osteodystrophy, seizures

“Aluminimum amount of feces”

Question 20

Calcium carbonate: tox?

Answer 20

Antacid general tox = alter gastric/urinary pH or delay gastric emptying -> affect other drugs; hypokalemia

Specific to Ca carbonate: hypercalcemia, rebound acid increase.

Can chelate and decr effectiveness of other drugs (ex tetracycline)

Question 21

Magnesium hydroxide: tox?

Answer 21

Antacid general tox = alter gastric/urinary pH or delay gastric emptying -> affect other drugs; hypokalemia

Specific to Mg hydroxide: diarrhea, hyporeflexia, hypotension, cardiac arrest

“Mg = Must Go to the bathroom”

Question 22

Class?

Magnesium hydroxide

Magnesium citrate

Polyethylene glycol

Lactulose

Answer 22

Osmotic laxatives

Question 23

Osmotic laxatives: mech?

(Magnesium hydroxide

Magnesium citrate

Polyethylene glycol

Lactulose)

Answer 23

Provide osmotic load to drive water out

Lactulose treats hepatic encephalophy (gut flora degrade it into lactic acide and acetic acid -> promotes nitrogen excretion as NH4+

Question 24

Osmotic laxatives: use?

(Magnesium hydroxide

Magnesium citrate

Polyethylene glycol

Lactulose)

Answer 24

Constipation

Lactulose: hepatic encephalopathy

Question 25

Osmotic laxatives: tox? (Magnesium hydroxide Magnesium citrate Polyethylene glycol Lactulose)

Answer 25

diarrhea dehydration abuse by bulimics

Question 26

Infliximab: mech?

Answer 26

Monoclonal antibody to TNF-a

Question 27

Infliximab: use?

Answer 27

Crohn's Ulcerative colitis rheumatoid arthritis ank spondylitis psoriasis

Question 28

Infliximab: tox?

Answer 28

Infection (possible reactivation of latent TB) fever hypotension

Question 29

sulfazalazine: mech?

Answer 29

combination of sulfapyridine (antibacterial) + 5-aminosalicylic acid (anti-inflammatory) Activated by colonic bacteria

Question 30

Sulfasalazine: use?

Answer 30

Ulcerative colitis Crohn's

Question 31

Sulfasalazine: tox?

Answer 31

Malaise nausea sulfonamide tox decr sperm count (reversible)

Question 32

metoclopramide: mech?

Answer 32

D2 receptor antagonist. decr resting tone, contractility, LES tone, motility does not change colon transport time

Question 33

metoclopramide: use?

Answer 33

diabetic and post-surg gastroparesis (paralysis) Anti-emetic

Question 34

metoclopramide: tox?

Answer 34

incr parkinsonian effects restlessness, drowsiness, fatigue, depression, nausea, diarrhea. Interacts with digoxin and diabetic agents

Question 35

metoclopramide: CI in what patients?

Answer 35

pts with small bowel obstruction Parkinson dz patients (D1-receptor blockade)

Question 36

Odansetron: mech?

Answer 36

5-HT₃ antagonist; decr vagal stimulation Powerful central-acting antiemetic "Keep on dancing with odansetron!"

Question 37

Odansetron: use?

Answer 37

control vomiting post-op patients undergoing cancer chemo

Question 38

Odansetron: tox?

Answer 38

headache constipation

Question 39

Diphenoxylate: mech?

Answer 39

binds mu receptors in GI; slows motility

Question 40

Diphenoxylate: use?

Answer 40

opiate anti-diarrheal (similar to meperidine - opioid agonist) in low doses, can slow gut motility with no euphoric effects packaged with atropine to discourage abuse!

Question 41

Treatment for Crohn's disease? (5)

Answer 41

Corticosteroids Azathioprine Methotrexate Infliximab Adalimumab

Question 42

Treatment for Ulcerative Colitis? (4)

Answer 42

ASA preparations (sulfasalazine) 6-mercaptopurine infliximab Colectomy

Question 43

Treatment for hepatic encephalopathy?

Answer 43

Lactulose (bacterial action -\> acid produced -\> NH3 becomes NH4, ammonium trap) Low protein diet (less nitrogen intake) Rifaximin (kills intestinal bacteria)

Question 44

Treatment for Crigler-Najjar syndrome? | (type I, Type II)

Answer 44

Type I: plasmapheresis, phototherapy Type II (less severe): phenobarbital (incr liver enzyme synthesis)

Question 45

Treatment for Wilson disease?

Answer 45

Penicillamine or Trientine

Question 46

Treatment of hereditary hemochromatosis?

Answer 46

- repeated phlebotomy - Iron chelation (deferasirox, deferoxamine)