pharmacology Acid suppression therapy H2 blockers Proton pump inhibitors Bismuth, sucralfate Misoprostol Octreotide Antacid use Osmotic laxatives Sulfasalazine Ondansetron Metoclopramide Orlistat

Question 1

Proton pump inhibitors work on pumps that exchange which two ions?

Answer 1

Hydrogen and potassium

Question 2

H2 blockers work on which stomach cell type?

Answer 2

Parietal cells

Question 3

Muscarinic antagonists work on which two cell types in the stomach?

Answer 3

Enterochromaffin-like cells (with M1 receptors) and parietal cells (with M3 receptors)

Question 4

Why are misoprostol, sucralfate, and bismuth useful in treating gastric ulcers?

Answer 4

These drugs have a protective effect on the mucosa underlying the ulcers

Question 5

Where does somatostatin act?

Answer 5

Somatostatin acts on enterochromaffin-like cells via ST2 receptors

Question 6

A surgeon damages the vagus nerve while operating. What type of GI therapy would be directly impacted?

Answer 6

Muscarinic antagonists, because the vagus nerve stimulates the M1 and M3 receptors

Question 7

A man has been taking an antacid for GERD pain. What is the mechanism for this drug and where does it target?

Answer 7

Antacids work in the stomach lumen and block the secretion of acid, or H+

Question 8

What type of cell in the antrum is stimulated by food? What hormone is stimulated by food to promote gastric acid secretion?

Answer 8

G cell; gastrin

Question 9

If a patient is deficient in gastrin, which cells and receptors will be understimulated in the fundus?

Answer 9

Parietal cells and ECLs (both have G [CCK-B] receptors that are stimulated by gastrin)

Question 10

A patient has a gastric ulcer causing severe pain. Name at least two medications can be given to help with ulcer healing?

Answer 10

Misoprostol, sucralfate, bismuth

Question 11

You study stomach gastrin activity. You administer food to rats and take several biopsies. Which stomach area will show the most activity?

Answer 11

The antrum

Question 12

Most gastric acid secretion (and the actions of medications that inhibit it) can be found in which area of the stomach?

Answer 12

The fundus

Question 13

Give at least two examples of H2 blockers.

Answer 13

Cimetidine, ranitidine, famotidine, nizatidine (take H2 blockers before you dine, & table for 2 to remember H2)

Question 14

What substance is the endogenous agonist of the H2 receptor?

Answer 14

Histamine

Question 15

What is the effect of H2 blockers on parietal cells?

Answer 15

Reversible decrease of hydrogen ion secretion

Question 16

Name at least two clinical uses of H2 blockers.

Answer 16

Peptic ulcers, gastritis, mild esophageal reflux

Question 17

A patient takes over 10 medications for various reasons. You are worried about drug interactions. Which H2 blocker should you avoid?

Answer 17

Cimetidine, as it causes inhibition of cytochrome P-450 and may alter the metabolism of other drugs

Question 18

Which two H2 blockers can decrease the renal excretion of creatinine?

Answer 18

Ranitidine and cimetidine

Question 19

A 50-y/o man starts a gastritis medication that inhibits cytochrome P-450. What adverse effects for this drug are seen specifically in men?

Answer 19

Prolactin release, gynecomastia, impotence, decreased libido (cimetidine is a P-450 inhibitor and has antiandrogenic effects)

Question 20

A 47-year-old woman has developed confusion, dizziness, and headaches since starting an H2 blocker. What is happening?

Answer 20

Cimetidine (able to cross the blood-brain barrier, unlike other H2 blockers) can cause confusion, dizziness, and headaches

Question 21

A woman on a specific H2 blocker tells her doctor that she wants to get pregnant. The doctor says she needs to stop the H2 blocker. Why?

Answer 21

Cimetidine, the H2 blocker she is likely taking, is dangerous to the fetus, because it can cross the placenta

Question 22

A woman has unexpected galactorrhea. Her medications include sertraline, pantoprazole, cimetidine, aspirin, simvastatin. Is a drug to blame?

Answer 22

Yes, as cimetidine can increase prolactin levels, which may cause galactorrhea

Question 23

A 34-y/o woman has continued GERD pain despite ranitidine & is negative for Helicobacter pylori antigens. Specific drugs to try next?

Answer 23

Omeprazole, esomeprazole, pantoprazole, lansoprazole, dexlansoprazole (proton pump inhibitors)

Question 24

Proton pump inhibitors work by irreversibly inhibiting this protein in stomach parietal cells.

Answer 24

H+/K+ ATPase

Question 25

Name at least two conditions that are treated with proton pump inhibitors.

Answer 25

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

Question 26

A patient has been using proton pump inhibitors for a long time. His level of which divalent electrolyte is likely decreased?

Answer 26

Magnesium

Question 27

Before starting a man on an H+/K+ ATPase inhibitor, you explain to him that there are some associated risks. What are some of these?

Answer 27

C. difficile infection, pneumonia, hip fractures, hypomagnesemia (with long-term use) (these are proton pump inhibitor side effects)

Question 28

A man presents with traveler's diarrhea. What two drugs might you choose to help reestablish the pH gradient in the mucous layer?

Answer 28

Bismuth and sucralfate

Question 29

Misoprostol is a ____ analog.

Answer 29

Prostaglandin E1

Question 30

Misoprostol increases the production and secretion of the ____ barrier and decreases the production of ____.

Answer 30

Gastric mucous; acid

Question 31

A patient with rheumatoid arthritis starts misoprostol after being intolerant to her prior treatment. What was the complication?

Answer 31

Peptic ulcers induced by NSAIDs (misoprostol increases gastric mucous production and decreases acid production)

Question 32

A neonate is noted to be cyanotic on the third day of life. What medication should be ordered immediately?

Answer 32

Misoprostol, which maintains a patent ductus arteriosus, allowing pulmonary and systemic circulations to mix in cases of heart disease

Question 33

A woman is given misoprostol at 42 weeks' gestation. Why?

Answer 33

To induce labor

Question 34

Within what population is misoprostol contraindicated?

Answer 34

Women of childbearing potential (it is an abortifacient)

Question 35

A 22-year-old woman requests a chemical abortion of her pregnancy. She receives a PGE1 analog. What side effect should she expect?

Answer 35

Diarrhea (she has likely been given misoprostol for her chemical abortion)

Question 36

A patient presents with bleeding esophageal varices. What is the mechanism of action of a drug that can acutely help abort the bleeding?

Answer 36

Octreotide is a long-acting somatostatin analog that inhibits actions of many splanchnic vasodilatory hormones

Question 37

A patient on pharmacologic treatment for a VIPoma experiences nausea, cramps, and steatorrhea. What medication is she likely taking?

Answer 37

Octreotide

Question 38

• A man with recent onset of excessive growth hormone secretion and a woman with a carcinoid tumor both could both benefit from what drug

Answer 38

Octreotide

Question 39

A 54-y/o woman being managed for CHF and hypothyroidism has started taking daily antacids. How might this affect her other medications?

Answer 39

Interference with absorption, bioavailability, and urinary excretion by altering gastric and urinary pH and delaying gastric emptying

Question 40

Name at least two compounds commonly used as antacids.

Answer 40

Aluminum hydroxide, calcium carbonate, magnesium hydroxide

Question 41

Diarrhea, hyporeflexia, hypotension, cardiac arrest, and hypokalemia are side effects of which antacid?

Answer 41

Magnesium hydroxide (Mg = must go to the bathroom)

Question 42

A young patient is overusing antacid calcium carbonate. What toxicities does this cause?

Answer 42

Hypercalcemia, rebound acid increase

Question 43

All antacids cause what electrolyte abnormality if overused?

Answer 43

Hypokalemia

Question 44

A patient who heavily self-medicates her GERD complains of dizziness and diarrhea. Which antacid is she likely overusing?

Answer 44

Magnesium hydroxide (can cause diarrhea and hypotension)

Question 45

A patient has hypophosphatemia and osteodystrophy. What medication is he likely chronically overusing to treat his GERD?

Answer 45

Aluminum hydroxide

Question 46

A patient with GERD needs to start tetracycline for an infection. Why is it important for you to check the medication list before starting?

Answer 46

Calcium carbonate antacids can chelate and reduce the effectiveness of certain other oral medications, such as tetracycline

Question 47

A patient suffering from both constipation and hepatic encephalopathy should be given which medication?

Answer 47

Lactulose, since this addresses both problems

Question 48

A patient with a history of bulimia is found to be dehydrated. Abuse of what GI medication could contribute to this finding?

Answer 48

Osmotic laxatives

Question 49

How does lactulose treat hepatic encephalopathy?

Answer 49

The gut flora degrades lactulose into lactic and acetic acid, promoting nitrogen excretion as NH4+ and reducing NH3 levels

Question 50

For a 24-year-old man with ulcerative colitis, you prescribe a medication that is a combination of two drugs. What are these?

Answer 50

Sulfapyridine and 5-aminosalicylic acid (the medicine is sulfasalazine)

Question 51

What is the function of sulfapyridine?

Answer 51

It is an antibiotic

Question 52

What activates sulfasalazine in the gut? Be specific

Answer 52

Colonic bacteria activate sulfasalazine

Question 53

A patient is on sulfasalazine. What two diseases is the drug typically used to treat?

Answer 53

Crohn disease (for the colitis component) and ulcerative colitis

Question 54

A 30-year-old man starts on a drug composed of sulfapyridine and 5-aminosalicylic acid for Crohn disease. Side effects to be monitored for?

Answer 54

Reversible oligospermia, malaise, nausea, sulfonamide toxicity (this is sulfasalazine)

Question 55

A patient is found to have Crohn ileitis and asks if he can be started on sulfasalazine. What is the appropriate response?

Answer 55

Sulfasalazine would be ineffective, because it is activated by colonic bacteria and thus has no effect proximal to the colon

Question 56

What component of the sulfasalazine is known to be anti-inflammatory?

Answer 56

5-aminosalicylic acid

Question 57

Ondansetron is an antagonist of what receptor type?

Answer 57

5-hydroxytryptamine3

Question 58

Ondansetron is used to control vomiting primarily in which two settings?

Answer 58

After surgery and in conjunction with cancer chemotherapy (if you are feeling queasy at a party, keep on dancing with ondansetron)

Question 59

You give a 47-year-old woman a 5-HT3 antagonist for her nausea while she gets chemotherapy. What two main toxicities should you look for?

Answer 59

Headache and constipation (this is ondansetron)

Question 60

What is the mechanism of action for ondansetron?

Answer 60

It binds 5-HT3 receptors and antagonizes them, decreasing vagal stimulation

Question 61

What is the mechanism of action of metoclopramide?

Answer 61

It is a dopamine receptor antagonist (specifically the D2 receptor)

Question 62

A man with HF and diabetes is receiving a D2 receptor antagonist for gastroparesis. What two types of drugs may cause interactions?

Answer 62

Digoxin and diabetic agents (this is metoclopramide)

Question 63

Metoclopramide is contraindicated in patients with what serious gastrointestinal disorder?

Answer 63

Small bowel obstruction; it is prokinetic and thus will worsen the discomfort of these patients

Question 64

On what parts of the gastrointestinal tract does metoclopramide act?

Answer 64

Lower esophageal sphincter (increases tone and contractility), stomach, small bowel (increases motility) (no effect on colon)

Question 65

Give at least two clinical uses of metoclopramide.

Answer 65

Diabetic gastroparesis, postsurgical gastroparesis, antiemesis

Question 66

A Parkinson disease patient with profuse vomiting asks for metoclopramide. Why does the doctor disagree with this choice?

Answer 66

Metoclopramide, a D2 receptor antagonist, can cross-react with and block D1 receptors, exacerbating parkinsonian symptoms

Question 67

A diabetic man is given a drug that causes restlessness, drowsiness, and nausea. Does this drug impact colon transit time?

Answer 67

No, as this is metoclopramide

Question 68

A 74-y/o woman has hypovolemia due to gastroenteritis. As the resident, would you start with ondansetron or metoclopramide for her nausea?

Answer 68

Ondansetron (metoclopramide is useful in GI-based nausea but has a greater risk of adverse effects in the elderly)

Question 69

A man wants a refill of a drug medication a previous doctor prescribed for weight loss. He says it gives him greasy stools. What drug is it?

Answer 69

Orlistat (inhibits gastric and pancreatic lipase)

Question 70

A patient asks about a weight loss drug she saw on TV, with greasy stools and vitamin deficiencies as side effects. How does the drug work?

Answer 70

It inhibits gastric and pancreatic lipase (this is orlistat)