GI drugs Flashcards
What is the tx of choice for acute ulcers?
antiacids
what type of therapy is needed to reduce the rate of recurrence for gastric ulcers?
antibiotic therapy
What do all the antibiotic therapies for the tx of ulcers have in common?
They all contain a PPI
what medications are included in the bismuth quadruple therapy?
bisuth, metro, tetra, and PPI
what is included in the concomitant quadruple therapy?
clarith, metro, amox and ppi
what is included in the triple therapy?
clarith, metro or amox and ppi
which tx for ulcers shows the greatest eradication rates?
the bismuth and concomitant quadruple therapy, triple therapy is old news baby
What two proton pump drugs do we need to know?
omeprazole and lansoprazole
You have an elderly pt with who just recently had a stent placed due to an MI so they put them on clopidogrel but now they have the GERD. What drug would you not recommend ?
omeprazole because its actions on cyp450 might inhibit the conversion of clopidogrel to its active form.
Can you have rebound gastric acidity after stopping a PPI?
yes yes you can
Is anyone PPI more efficacious than the other?
no they are all created equal
Clinical uses for PPI are?
Gerd- most effective agent
Peptic ulcer disease- more rapid symptom relief and faster healing than H2 anatagonists
NSAID induced ulcers
Prevention of stress gastritis
Zollinger-ellison syndrome- higher dose provides complete symptomatic relief
H2 receptor anatagonists?
Ranitidine
Cimetidine
famotidine
nizatidine
all of these are available OTC for acute gastritis
true or false: H2 blockers are better at suppressing nocturnal acid secretion than meal stimulated acid secretion?
True
True or false bothe PPis and H2 blockers are rapidly absorbed?
True
Clinical use of H2 blockers?
Gerd- if its infrequent
Peptic ulcer disease - but PPI is better
Stress-related gastritis- reduces bleeding when given IV
H2 blocker effects on CNS?
slurred speech, confusion more common with cimetidine
You have a pt taking ketaconazole (for something already forget possibly candida) and they have intermittent Gerd. should you use a PPI or H2 blocker?
neither they need to suck it up because all anitsecretory agents decrease ketaconazole absorption by causing an increase in gastric PH
out of all the H2 blockers which one has the most drug interactions?
Cimetidine
What are the drug to drug interactions brought on by cimetidine?
it inhibits cytochrom p450 oxidative metabolism.
This can increase the effects of many drugs. some of which are warfarin, phenytoin, carbamazepine, ketoconazole
which agent is a mucosal protective agent?
sucralfate
How does sucralfate work?
it binds to necrotic ulcer tissue to form a protective barrier. Single dose can last 6 hours
Should you administer sucralfate with an antacid or h2 blocker?
no becasue it is activated at a acid of less than 4.
true or false sucralfate has systemic absorption?
false
Whats the most common adverse effect of sucralfate?
constipation
So for antisecretory drugs we have?
H2 blockers
PPis
sucralfate
prostaglandins
true or false: Misoprostol is a prostaglandin?
true
what is the pharmacodynamic affect of prostaglandins?
inhibits cAMP formation which results in decreased H+ secretion (most important clinical effect)
does misoprostol stimulate acid neutralizing HCO3 formation?
yes- but most important effect is decrease secretion of H+
How rapid of an onset does misoprostol have?
this baby kicks in within 30 minutes but has a very short half life also 30 minutes
If someone has an Nsaid-induced ulceration but they do not want to take a PPI what is the next best drug?
Misoprostol
You have a pregnant pt with a NSAID ulceration and you know misoprostol work super well for this. Are you going to prescribe it for this pregnant pt?
NO because of its increase in uterine motility
Properties of an ideal antacid?
- should raise PH rapidly to 4-5
- should be long acting
- Should have no undesirable side effects
Should an antacid contain NAHCO3?
No because it results in the highest levels of systemic actions. you do not want systemic actions in antacids
If an antacid contains AL++, Mg+ and Ca++ how are they absorbed?
they are absorbed less completely and with normal renal function accumulation (however they usually raise urine PH by 1 unit)
effectiveness of an antacid is defined by mEq of acid neutralizing capacity however how are they dosed in clinical use?
dosed by titration until symptom relief is achieved
when should antacids be taken?
1 hour to 3 hours after a meal so that they are not excreted quickly and can last as long as possible
Which primary neutralizing ingredient of an antacid can cause rebound secretion of acid?
Calcium (tums) due to its effect on gastrin release
What primary neutralizing ingredient binds to phosphate in the gut and is also used in chronic renal failure to hyperphosphatemia
this is aluminum- main side effect is constipation
what can chronic use of an aluminum antacid result in?
may lead to CNS toxicity (encephalopathy)
What antacid causes osmotic diarrhea and is often added to antacid preparations that contain Al++
Magnesium (milk of magnesia)
true or false: Milk of magnesia can be used if renal disease is present?
false
why is NAHCO3 contraindicated for long term use?
due to systemic effects: Na+ overload and alkalosis
when should sodium bicarb be avoided?
Pregnant, CHF, hypertension edema and renal failure
What laxatives are bulk forming?
psyllium
How does psyllium work?
it facilitates passage and stimulates peristalsis by absorption of water and subsequent bulk expansion
basically makes your poop bigger and thus pushes on your GI tract to stimulate the response of “hey get us the fuck out of here”
How does saline laxative agent work?
non-absorbable ions which cause osmotic retention of water inside the intestine leading to increased peristalsis
What are some saline (osmotic) laxatives?
Polyethylene glycol, Milk of magnesia, phosphate enema, and lactulose
What is the first line tx fro constipation?
polyethylene glycol aka miralax
You have someone who is getting a colonoscopy would you use high volume polyethylene glycol or low volume?
high volume is used for bowel cleansing prior to radiologic, surgical or endoscope procedures
Bisacodyl is a stimulant/irritant laxative how does it work?
thought to work by inducing low-grade inflammation in the bowel to promote accumulation of water and electrolytes which then stimulates peristalsis.
activates prostaglandin-Camp and NO-gCMP
True or false: Bisacodyl is the most widely abused class of laxative?
true
Which two laxatives are stool-wetting agents?
docusate ( a surfactant)
Mineral oil (lubricant)
what is docusate primary role?
used in prevention of constipation, often given when someone is starting an opioid
how does mineral oil work?
it coats the poop preventing the GI tract from absorbing the water from it
use in caution with children due to aspiration into the lungs
Loperamide is an opioid acting anti diarrheal, what is the mechanism of action?
it has effects on motility (decreased), intestinal secretion, and (increased) absorption and also has an anti-secretory activity against cholera toxin
One of your patients is going on vacation to an area where diarrhea runs rapid what anti diarhheal would you give?
Loperamide (imodium)
only thing is high doses can cross BBB
How doe the
polycarbophil (mitrolan) work?
this bad boy is like an ant (ants can lift like 100x there weight) mitrolan can absorb 60x weight in H2O
-can be used for diarrhea and prevents constipation
what are the three absorbent anti diarrheal drugs we need to know?
Kaolin, Pectin, bismuth subsalicylate (pepto bismol)
Hmm wonder how adSORBENTS work
Well they absorb toxins that cause irritation (remember the laxative drug that causes irritation), they can also absorb drugs, nutrients and digestive enzymes
Should you give bismuth subsalicylate (pepto bismol) to children under 12?
NO salicylate causes risk for reyes syndrome
Probiotics
If you know you know
