Gastrointestinal

Question 1

H2 blockers

Answer 1

"-dine"
Cimetidine
Ranitidine
Famotidine
Nizatidine

Reversible block of histamine H2 receptors = decreased H+ secretion by parietal cells

Question 2

Cimetidine toxicity

Answer 2

Potent inhibitor of cytochrome P450 (multiple drug interactions)
Antiandrogenic effects (prolactin release, gynecomastia, impotence, decreased libido in males)
Can cross BBB (confusion, dizziness, headaches) and placenta
Decrease renal excretion of creatinine (also seen with ranitidine)

Question 3

Proton pump inhibitors

Answer 3

"-prazole"
Omeprazole
Lansoprazole
Esomeprazole
Pantoprazole
Dexlansoprazole 

Irreversible inhibit H+/K+ ATPase in stomach parietal cells

Question 4

PPI toxicity

Answer 4

Increased risk of C. difficile infection and pneumonia

Hip fractures and decreased serum Mg2+ with long term use (can also affect B12 absorption)

Question 5

Bismuth, sucralfate

Answer 5

Bind to ulcer base, providing physical protection and allowing HCO3 secretion to reestablish pH gradient in mucous layer

Question 6

Misoprostol

Answer 6

PGE1 analog
Increases production and secretion of gastric mucous barrier
Decreases acid production

Question 7

Which drug(s) is/are used to increase ulcer healing and treat travelers’ diarrhea?

Answer 7

Bismuth

Sucralfate

Question 8

Which drug can be used to prevent NSAID induced peptic ulcers?

Answer 8

Misoprostol

NSAIDs block PGE1 production so treat with PGE1 analog

Question 9

Which drug can be used to maintain a PDA? Induce labor?

Answer 9

Misoprostol
Prostaglandins keep the ductus arteriosus open
Prostaglandins “ripen” the cervix to induce labor

Question 10

Misoprostol toxicity

Answer 10

PGE1 analog

Diarrhea
Contraindicated in women of childbearing potential (abortifacient)

Question 11

Octreotide

Answer 11

Long-acting somatostatin analog

Question 12

Which drug can be used in the treatment of acute variceal bleeds, acromegaly, VIPoma, and carcinoid tumors

Answer 12

Octreotide

Question 13

Octreotide toxicity

Answer 13

Long-acting somatostatin analog

Nausea
Cramps
Steatorrhea

Question 14

Antacids (3)

Answer 14

Aluminum hydroxide
Calcium carbonate
Magnesium hydroxide

Can affect absorption, bioavailability, or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying
All can cause HYPOkalemia

Question 15

Aluminum hydroxide overuse problems

Answer 15

Constipation ("aluMINIMUM amount of feces")
Hypophosphatemia
Proximal muscle weakness
Osteodystrophy
Seizures

Question 16

Calcium carbonate overuse problems

Answer 16

Hypercalcemia
Rebound acid increase

Can chelate and decrease effectiveness of other drugs (tetracyclines)

Question 17

Magnesium hydroxide overuse problems

Answer 17

Diarrhea (Mg = “M”ust “g”o to the bathroom)
Hyporeflexia
Hypotension
Cardiac arrest

Question 18

Osmotic laxatives

Answer 18

Magnesium hydroxide
Magnesium citrate
Polyethylene glycol
Lactulose

Provide osmotic load to draw water out
Use = constipation

Question 19

Added treatment benefit of lactulose

Answer 19

Osmotic laxative that also treats HEPATIC ENCEPHALOPATHY since gut flora degrade it into metabolites (lactic acid and acetic acid) that promote nitrogen excretion as NH4+

Question 20

Osmotic laxative toxicity

Answer 20

Diarrhea
Dehydration
May be abused by bulimics

Question 21

Infliximab

Uses?

Answer 21

Monoclonal antibody to TNF-a

Use = Crohn disease, ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, psoriasis

Question 22

Infliximab toxicity

Answer 22

Monoclonal AB to TNF-a

Infection (including reactivation of latent TB)
Fever
Hypotension

Question 23

Sulfasalazine

Uses?

Answer 23

Combination of sulfapyridine (antibacterial) and 5-aminosalicylic acid (anti-inflammatory)
Activated by colonic bacteria

Use = Ulcerative colitis, Crohn disease

Question 24

Sulfasalazine toxicity

Answer 24

Combination of sulfapyridine (antibacterial) and 5-aminosalicylic acid (anti-inflammatory)

Malaise, nausea, sulfonamide toxicity, reversible oligospermia

Question 25

Ondansetron (Zofran)

Answer 25

5-HT3 antagonist
Decreases vagal stimulation
Powerful central-acting antiemetic
“Keep on dancing with ondansetron”

Question 26

Ondansetron uses and toxicity

Answer 26

5-HT3 antagonist

Uses = controlling vomiting postoperatively and in patients undergoing cancer chemotherapy

Toxicity = headache, constipation

Question 27

Metoclopramide

Answer 27

D2 receptor antagonist
Increases resting tone, contractility, LES tone, motility
Does NOT influence colon transport time

Question 28

Which antiemetic can is used to treat diabetic and post-surgery gastroparesis?

Answer 28

Metoclopramide

Question 29

Metoclopramide toxicity

Answer 29

D2 receptor antagonist

Increased parkinsonian effects
Restlessness, drowsiness, fatigue, depression, nausea, diarrhea
Drug interaction with digoxin and diabetic agents
Contraindicated in patients with small bowel obstruction or Parkinson disease (D1 receptor blockade)