Anti-Ulcer Drugs - Fitz Flashcards
What medication replaces prostaglandins in the gastric mucosa?
Why would that even help?
Misoprostol
It is used for NSAID-induced ulcers because the loss of PGs will decrease mucus secretion and lead to damage!
Reasons why amoxicillin is a good choice for H pylori tx?
Efffective against gram -
Orally available
Acid stable
Mechanism of amoxicillin?
bactericidal
Cell wall inhibition
Mechanism of Clarithromycin?
Bacteriostatic
Protein synthesis inhibitor (50s rRNA)
What are two things important for the method a patient takes their tetracycline?
2 things - give with food (which is opposite of others)
Don’t take antacids! (chelator effect)
What is the mechanism and what are the side effects of tetracycline?
Mech:
Protein Synthesis inhibitor (30s)
Side effects: GI irritation Photosensitivity Discolor growing teeth (NO PREGOS or kids!)
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?
Rifabutin
-Inhibits DNA-dependent RNA polymerase
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?
Metronidazole!
- Disulfuram-like rxn with alcohol
- GI effects
- CNS toxicity
- teratogen?
What are the two mechanims of bismuth subsalicylate?
Antimicrobial - unclear how
Surface protection - Coats the surface and stimualtes secretion of Prostaglandin and HCO3
What kinds of side effects might you get from subsalicylate?
Vomiting, tinnitus, confusion, hyperthermia, respiratory alkalosis –> metabolic acidosis
Mechanism of H2 receptor agonists like cimetidine?
Competitive antagonists of H2 receptors
Decrease all forms of gastric acid secretion (esp. nocturnal)
Secondary effect - decrease cAMP (especially meal-time)
What drugs cause bradycardia and hypotension when given in rapid IV infusion?
H2 blockers like cimetidine and ranitidine
Infuse slow, and you’re good
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?
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
Please explain why it is so important that PPIs be given 30 minutes before a meal?
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!
Explain why PPI’s are only given once a day if their 1/2 life is shorter than that?
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
What stomach acid buffers should be combined to decrease their GI effects?
Alumnium hydroxide (causes constipation) and Mg Hydroxide (Causes diarrhea)
What are the three long-term concerns you should have for someone taking PPIs?
Hip fracture (decreased B12, Ca, and Zn absorption)
Increased respiratory and enteric infections
Increased gastrin (trying to get you to make more HCl)
What buffer acid medications cause systemic alkalosis?
Which alkalinize urine?
Ca carbonate and Na Bicarb cause alkalosis (Na bicarb more severe)
-They both also cause belching
One Na bicarb alkalinizes urine!
Which antibiotic won’t work with antacids?
Tetracycline!
Chelator!
Drug of choice for zollinger-ellison syndrome?
PPI’s
also choice for, GERD, and ulcers
What is zollinger ellison syndrome?
Gastrinoma tumors secrete a TON of gastrin, and BAM, you got all this HCl hanging around!
What does simethicone?
Just decrease gas pain through anti-inflammation
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?
Sucralfate
Like a band-aid binding to ulcer surface
It NEEDS acid in order to be activated and converted into paste
Side effects of misoprostol?
#1 = Causes abortions -diarrhea, nausea, cramping, abdominal pain
Do ionized or un-ionized molecules pass more freely through the stomach lining and kidney tubule lining?
Un-ionized
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?
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
