Upper GI Drugs Flashcards
Name four strategies to treat Peptic Ulcer Disease
Decrease gastric acid production
Neutralize gastric acid
Increase Mucosal Defenses
Eradicate H pylori
What is an ECL cell and what does it produce?
EnteroChromaffin- Like cell
Produces Histamine (H2)
What three chemicals
cause parietal cells to produce gastric acid?
Gastrin (made in the G cell)
Histamine (made in the ECL cell)
Acetyl Choline (from nerve cells)
How does negative feedback work in the stomach as pertains to gastric acid?
Gastric Acid in the antrum enters the D cell causing it to release Somatostatin (which “stops everything”) which enters the receptor on the G cell to stop Gastrin production.
What are the three types of medications that reduce gastric acid secretion and which one is irreversible?
H2 Receptor Antagonists are reversible
Proton Pump Inhibitors are irreversible
PGE1 analog (misopristol)
Which PUD treatment is “the perfect drug” and why?
PPIs because they only work where they are needed so there are no side effects and are 90-98% effective
Which GI drugs should be taken before a meal and which should be taken after a meal? Why?
Antacids after a meal so they wil have some acid to neutralize.
Before a meal: PPIs (before breakfast) and Sucralfate (in order to pre-coat the stomach)
What is the treatment coctail to eradicate H pylori?
PPI
Clarithromycin
Metronidazole or Amoxicillin
+/- bismuth subsalicylate
Why do some antacids combine Mg(OH)2 and CaCO3?
To balance the side effects:
Mg(OH)2 –> diarrhea
CaCO3 –> constipation
Your patient is a 65 year old female with HTN, adrenal insufficiency, kidney disease and heartburn. She asks if its okay to take Pepsid (Famotidine). What is your concern?
H2 antagonists have renal elimination so you need to change the dose accordingly.
Your patient has occaisional severe heartburn at night. Which medication do you recommend and why?
H2 blockers/antagonists work best at night because that is when H2 is the primary inducer of acid (less ACh and Gastin)
Your patient has early cirrhosis and GERD. What can you recommend to control the acid?
H2 blockers would be better than PPIs because PPIs have hepatic metabolism
True or False: Long term use of PPIs increase the risk of pneumonia, infections and carcinoma.
False.
This is a concern, but has not been proven by evidence.
PPIs have four proven adverse effects: two are common and two are rare. What are they?
Common:
Increased fracture risk & decreassed B12 absorption
(Due to changes in absorption of Ca++ and B12
in a less acidic environment)
Rare: Decreased Mg++ & increased risk of CKD
Which medication is the first choice
to treat Zollinger Ellison Disease?
PPIs
Your patient has Afib and is taking warfarin. He also needs an H2 receptor antagonist. Which do you chose and why?
Famotidine is better because is less of an CYP inhibitor than Cimetidine.
Which drug is more potent? Cimetidine or Famotidine?
Famotidine is 20-50 times more potent
You are doing your clinical rotation at Whitman Walker Clinic. You have a patient who is transgender and transitioning from male to female and needs an H2 blocker .
Which medication is the best choice?
Cimetidine: it has hormonal effects that cause gynocomastia and impotence in men, galactorrhea in women.
Why is it contraindicated to take sucralfate simultaneously with an antacid?
Because it needs a low pH to work properly.
You prescribed sucralfate to your patient who is taking many other medications. What do you need to explain to the patient?
Take the other medications first and wait two hours before taking the sucralfate. If you take the sucralfate first, you will not be able to absorb your other medications.
You are on your pediatrics rotation seeing a 3 year old boy with gastric reflux.
What medication must you tell the parents to avoid?
Pepto Bismol (bismuth subsalicylate)
because when it reacts with stomach acid
it produces salicytic acid (aspirin)
which can cause Reyes Syndrome.
Your 35 year old patient has a peptic ulcer and you advise her to take something to bind the ulcer to protect it. What do you recommend?
What is an added bonus to this medicaiton?
What odd side effect should you tell her about?
Bismuth Subsalicilate
Bonus: antimicrobial
Side Effect: blackens tongue and stool
Most of the drugs on our list are aimed at reducing stomach acid. Which two also target the enzyme pepsin?
Sucralfate
Bismuth subsalicylate
Your patient is 4 months pregnant and suffering from severe heartburn. Which heartburn medication must you avoid?
Misoprostol (PGE1 analog)
It can cause a miscarriage
(It causes uterine contractions
so it is used for abortions and to treat postpartum bleeding)
What are the four main MOAs (methods of action)
of metaclopramide?
Increases ACh release in myenteric plexus
Increases smooth muscle response to ACh
Increases esophageal sphincter tone
Decreases pyloric sphincter tone (increasing gastric emptying)
Which antiemetic needs to be given BEFORE chemo or surgery to prevent nausea and vomiting?
Odansetron (Zofran)
Why is it not a good idea to give Metaclopramide long term?
It is a D2 receptor antagonist resulting in Parkinsonian symptpoms such as tardive dyskenesia
(Black box warning re irreversible muscle spasms)
What is the MOA of Odansetron?
5HT3 antagonist
What are the side effects of Odansetron?
Constipation
Headache
What are the six targets/strategies to treat nausea/vomiting?
5-HT3 receptor antagonists
Central-acting dopamine receptor antagonists
H1 receptor antagonist
Muscarinic receptor antagonist
Neurokinin receptor antagonist
Cannabinoid receptor agonist
