Anti-Ulcer Drugs - Fitz

Question 1

What medication replaces prostaglandins in the gastric mucosa?
Why would that even help?

Answer 1

Misoprostol

It is used for NSAID-induced ulcers because the loss of PGs will decrease mucus secretion and lead to damage!

Question 2

Reasons why amoxicillin is a good choice for H pylori tx?

Answer 2

Efffective against gram -
Orally available
Acid stable

Question 3

Mechanism of amoxicillin?

Answer 3

bactericidal

Cell wall inhibition

Question 4

Mechanism of Clarithromycin?

Answer 4

Bacteriostatic

Protein synthesis inhibitor (50s rRNA)

Question 5

What are two things important for the method a patient takes their tetracycline?

Answer 5

2 things - give with food (which is opposite of others)

Don’t take antacids! (chelator effect)

Question 6

What is the mechanism and what are the side effects of tetracycline?

Answer 6

Mech:
Protein Synthesis inhibitor (30s)

Side effects:
GI irritation
Photosensitivity
Discolor growing teeth
(NO PREGOS or kids!)

Question 7

A patient was on a drug for treating H. Pylori and he is scared because his tears are orange! He also happens to have liver failure…

What drug is he on?
What is the mechanism of that drug?

Answer 7

Rifabutin

-Inhibits DNA-dependent RNA polymerase

Question 8

Another patient is on a drug for H. Pylori too. You told him not to drink, but he did anyway and comes into your office a total wreck!
What med is he on?

What other side effects can this drug cause?

Answer 8

Metronidazole!

• Disulfuram-like rxn with alcohol
• GI effects
• CNS toxicity
• teratogen?

Question 9

What are the two mechanims of bismuth subsalicylate?

Answer 9

Antimicrobial - unclear how

Surface protection - Coats the surface and stimualtes secretion of Prostaglandin and HCO3

Question 10

What kinds of side effects might you get from subsalicylate?

Answer 10

Vomiting, tinnitus, confusion, hyperthermia, respiratory alkalosis –> metabolic acidosis

Question 11

Mechanism of H2 receptor agonists like cimetidine?

Answer 11

Competitive antagonists of H2 receptors
Decrease all forms of gastric acid secretion (esp. nocturnal)

Secondary effect - decrease cAMP (especially meal-time)

Question 12

What drugs cause bradycardia and hypotension when given in rapid IV infusion?

Answer 12

H2 blockers like cimetidine and ranitidine

Infuse slow, and you’re good

Question 13

An older male patient comes in believing he is growing breasts. He has been on medication for GERD for a year now.

What might a female using the same medication in high doses complain of as a side effect?

What is the mechanism behind these adverse effects?

Answer 13

Galactorrhea.

Why?
It sounds like he is having a side effect to Cimetidine specifically. Gynecomastia
In females, a serious adverse effect is galactorrhea

In high doses drug can cause decreased binding of DHT to androgen receptor. This decreases estrogen metabolism and increases prolactin

Question 14

Please explain why it is so important that PPIs be given 30 minutes before a meal?

Answer 14

1) Given in fasting state will decrease crushing and exposure of pill to acid
2) In fasting only 10% of P-pumps are active, more will be active when you eat in 30 mins and at that point the PPI is already in your blood stream!

Question 15

Explain why PPI’s are only given once a day if their 1/2 life is shorter than that?

Answer 15

They irreversibly bind to proton pumps. It takes 18 hrs to make new pumps and then bam! You take some more PPI.
Full inhibition will take 3-4 days

Question 16

What stomach acid buffers should be combined to decrease their GI effects?

Answer 16

Alumnium hydroxide (causes constipation)
and
Mg Hydroxide (Causes diarrhea)

Question 17

What are the three long-term concerns you should have for someone taking PPIs?

Answer 17

Hip fracture (decreased B12, Ca, and Zn absorption)

Increased respiratory and enteric infections

Increased gastrin (trying to get you to make more HCl)

Question 18

What buffer acid medications cause systemic alkalosis?

Which alkalinize urine?

Answer 18

Ca carbonate and Na Bicarb cause alkalosis (Na bicarb more severe)
-They both also cause belching

One Na bicarb alkalinizes urine!

Question 19

Which antibiotic won’t work with antacids?

Answer 19

Tetracycline!

Chelator!

Question 20

Drug of choice for zollinger-ellison syndrome?

Answer 20

PPI’s

also choice for, GERD, and ulcers

Question 21

What is zollinger ellison syndrome?

Answer 21

Gastrinoma tumors secrete a TON of gastrin, and BAM, you got all this HCl hanging around!

Question 22

What does simethicone?

Answer 22

Just decrease gas pain through anti-inflammation

Question 23

You are following your patient in the ICU and it is discovers she has a stress-induced ulcer.
Tx of choice?
How does it work?

Answer 23

Sucralfate
Like a band-aid binding to ulcer surface
It NEEDS acid in order to be activated and converted into paste

Question 24

Side effects of misoprostol?

Answer 24

#1 = Causes abortions
-diarrhea, nausea, cramping, abdominal pain

Question 25

Do ionized or un-ionized molecules pass more freely through the stomach lining and kidney tubule lining?

Answer 25

Un-ionized

Question 26

So a weak acid drug is going down the kidney tubule.
You have alkalinated your urine with NaHCO3.
Will more or less of the drug now be excreted?

Answer 26

more excreted

Why?
The alkaline environment will deprotonate the weak acid, it is now charged and is stuck in the lumen to be excreted

If it were a weak base, the alkaline environment will compel the molecule to remain in it’s uncharged form and less of the drug will be excreted