Transcript Pharm Review #1

Pharm Review #1
#1
• Esomeprazole is one of the medications prescribed for a patient you are
seeing today in your practice. Which one of the following statements best
describes the actions or effects of esomeprazole and other drugs in its
class?
• A) Cause strong systemic atropine-like (antimuscarinic) effects that limit
their use in patients
• B) Inhibit gastric acid secretion by simultaneously and competitively
blocking the actions of the agonists histamine, Ach, and gastrin, on their
parietal cell membrane receptors
• C) Neutralize gastric acid faster than any other classes of drugs indicated
for peptic ulcer disease or GERD
• D) Profoundly inhibit an ATPase located on parietal cell membranes,
thereby inhibiting acid secretion
• E) Tend to cause bradycardia by antagonizing the positive chronotropic
effects of histamine on cardiac H1 receptors.
#1 Answer
•
•
•
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D.
It ends prazole. Therefore PPI.
“Prazoles” – no antimuscarinic activity.
Their antisecretory action occurs downstream of
agonists such as Ach, histamine, and gastrin, and do
not involve blockade/antagonism of those ligands on
their receptors
• No neutralizing activity
• Histamine does exert positive chronotropic effects on
the heart, but that is not antagonized by any PPI
#2
• A patient has severe GERD. In addition to providing some immediate
symptom relief, for which you will prescribe usually effective doses of an
OTC combination antacid product, you want to suppress gastric acid
completely as possible. Which drug is best suited for achieving that goal?
• A) Atropine
• B) Calcium carbonate
• C) Cimetidine
• D) Esomeprazole
• E) Misoprostol
#2 Answer
• D
• Since PPIs work on the “final common
pathway”, they are the most effective for acid
secretion.
• The papers also discussed how PPIs are most
effective; better than H2 blockers, though they
do take longer than H2 blockers to work.
#3
• Patient with multiple medical problems is taking several drugs
including theophylline, warfarin, quinidine, and phenytoin. Despite
the likelihood of interactions, dosages of each were adjusted
carefully so their plasma concentrations and effects are acceptable.
However, the patient suffers from some GI distress and starts taking
a drug provided by one of his “well-intentioned” friends. He
presents with excessive or toxic effects from all his other
medications, and blood tests reveal that plasma concentrations of
all the prescribed drugs are high. Which drug did the patient most
likely self-prescribe and take?
• A) Antacid (typical Mg-Al combination
• B) Cimetidine
• C)Famotidine
• D) Nizatidine
• E) Ranitidine
#3
• B.
• Cimetidine differs from the other H2 blockers.
It is a very strong inhibitor of CYP450
– CYP1A2, 2C9, 2D6, and 3A4
• Antacids absorb drugs in the gut and inhibit
their absorption.
#4
• You recommend several antacid brands for the patient to try. All the
products you list are combination products that contain a magnesium salt
and an aluminum salt. What is the main rationale for the combination
products.
• A) Al salts counteract the gastric mucosal-irritating effects of Mg salts
• B) Al salts require activation by an Mg-dependent enzyme in order to
inhibit the parietal cell proton pump
• C) Mg salts cause a diuresis that helps reduce systemic accumulation of
the Al salt by increasing renal Al excretion
• D) Mg salts potentiate the ability of AL salts to inhibit gastric acid
secretion
• E) Mg salts tend to cause a laxative effect (increased gut motility) that
counteracts the tendency of an l salt to cause constipation
#4
• E. Mg can be used alone as a laxative effect.
Aluminum tend to cause constipation.
• Patient comes in stating that they are
currently taking naproxen for their
osteoarthritis. They are worried that they may
get peptic ulcer disease from the medication.
What is the mechanism of action for the drug
that you would prescribe to prevent the PUD?
Misoprostol
• inhibits gastric acid secretion and promites
secretion of mucus
• A 60 year Type 2 diabetic comes into your
office complaining that food seems to get
stuck in his stomach. After a further work up
of something discussed in a future CM lecture,
you diagnose the patient with diabetic
gastroparesis. You then decide to prescribe a
medication that works by blocking the d2
receptor to promote motility. What is the side
effect of this medication that you must be
worried about?
Metoclopramide
• Aes: Extrapyramidal effects (dystonias),
seizures, hyperprolactinemia
• As a resident, you find yourself managing a
patient recovering from a coronary bypass
procedure due to a STEMI. Aside from giving
the typical regimen of aspirin, metoprolol,
lisinopril, and atorvastatin. What else might
you prescribe to ensure the patient doesn’t
undergo any unnecessary straining?
• Docusate
• The previous patient has been found to also
need a calcium channel blocker. What type of
calcium channel blockers are found to have a
higher association with constipation?
• Non-dihydropyridines
• A patient comes to you complaining you of
constipation even after taking bulk-forming
agents. You suggest that they should take a
medication that tells the nerves in their GI
tract to stimulate movement of their food.
Weeks later, because you forgot to tell the
patient when to stop the medication, they
come back later still on the medication. What
might they be at risk for?
Stimulant Laxatives – Bisacodyl/Senna
• Fluid/electrolyte imbalance. Hypokalemia.
• There is a synthetic disaccharide in which
there is bacterial fermentation in the colon to
a low-molecular weight acids, resulting in an
osmotic effect. This osmotic effect allows for
the medication to be a laxative. However, this
medication is also used for the management
of another condition. What does this
medication do for this other condition?
Lactulose
• Often used in the management of hepatic encephalopathy
due to cirrhosis
• Lowers blood ammonia
– Laxative effect reduces time for ammonia absorption
– Leaches ammonia from the circulation into the colon and increases
bacterial uptake by colonic bacteria
– Interferes with the uptake of glutamine in the small intestine and
its metabolism to ammonia
• In CM, we learned to use polyethylene glycol
to treat a kid with constipation. What is the
mechanism behind this medication that would
make this preferable over sorbitol and
lactulose?
– Organic polymers poorly absorbed but NOT fermented in the
colon, so less bloating and cramping
• Miralax
• One of the patients in the hospital you are
currently attending to just had a small bowel
resection. You notice that the attending gave
them a medication for 7 days po to accelerate
the recovery of function. What is the
mechanism of action for this medication?
Alvimopan
• Peripherally-acting mu-opioid receptor
antagonists in theGI tract  decrease the
constipating effects of opioids without
impacting analgesic effects on the CNS
• On a chart for a patient, you notice the
attending wrote that a patient has carcinoid
syndrome and is currently taking a medication
for it. You want to impress the attending with
your vast knowledge of pharmacological
agents. What is the side effect that might
occur from this medication?
Octreotide
• Cholelithiasis – gall stones.
– Nausea, diarrhea, abdominal pain
– Local injection pain
– Steatorrhea (reduces dietary fat absorption)
• A woman comes to you complaining of
symptoms that lead to the diagnosis of
Diarrhea predominant IBS. Aside from
suggesting that they keep a diary of possible
trigger foods, you tell the patient to pick up
Loperamide over the counter. What is the
mechanism of action of this medication?
• Opioid agonists: selectively act at intestinal
opioid receptors with little CNS activity;
decrease motility
• The loperamide and trigger food avoidance
given in the last patient did not seem to work.
Therefore, you refer the patient a specialized
physician who is a part of a restricted
distribution program and can prescribe a
certain medication. The medication is highly
restricted due to what possible adverse
effects?
Alosetron
– Severe constipation** with complications, e.g., obstruction,
perforation, impaction, toxic megacolon, secondary colonic ischemia
– Ischemic colitis (rectal bleeding, bloody diarrhea, or new or
worsening abdominal pain); d/c immediately
• As a primary care physician, you see patients
with high LDL levels every day. One patient
came in with a severely elevated LDL and
complained of recent diarrhea. You decided to
not only prescribe atorvastatin, but also
cholestyramine. Why might this be a problem
if a patient is on several other medications?
Bile-Salt Binding Resins
• DIs: bind to and decrease bioavailability of
many drugs; separate doses
• Woman comes into your office complaining
that the high fiber diet another physician told
her to use did not work for her constipation
predominant IBS. She refuses any OMM
treatment and demands that she wants a
medication. What is the mechanism of action
this “2nd line” agent?
• Lubiprostone –
• MOA: selectively activates intestinal ClC-2 chloride channels
– Increases intestinal fluid secretion
– Increases intestinal motility
• A 40 year old woman comes in looking for a
short term management of her IBS that
cannot be effectively treated with other
agents. You suggest a possible last line
medication. What could the patient be at a
higher risk for on this medication?
Tegaserod
• Warning: data indicate an increased risk of ischemic CV
events (unstable angina, MI, stroke)
– Contraindicated with CV disease
– Available in the US on a restricted basis only
• Patient asks for something to help with their
intestinal cramping and pain with their IBS. In
typical physician fashion, you oblige to their
demands and write them a prn for abdominal
pain prescription. What receptors do the drug
that you prescribe work on?
Antispasmodics
• MOA: muscarinic receptor antagonists; relax
intestinal smooth muscle, reduce motility
• A woman with a BMI of 33 comes in and states
that she wants to be as skinny as the models that
she sees on TV. She said that she is going to go on
a very low caloric diet, barely eating anything.
Aside from suggesting that she takes the healthy
diet approach rather than not eating anything,
you prescribe her a medication as a prophylaxis
against gallstones because patients don’t always
listen to your nutrition recommendations. What
drugs have an antagonistic effect to the one you
prescribed?
Drug Prescribed - Ursodiol
• fibric acid derivatives and estrogens are antagonistic (promote
gallstone formation)
• A patient in the ICU develops infectious
diarrhea. You diagnose the patient with C.
difficile. What do you instruct this patient not
to take with the first line medication?
Medication - Metronidazole
• Alcohol. Disulfram Reaction.
• The last medication you prescribed for the C.
difficile patient failed to eradicate the
problem. You note that the next medication
you are going to prescribe the patient has to
be delivered a certain way otherwise you
cannot give the full amount of coverage for
the patient. What route must the next
medication be given?
Vancomycin
• oral.
• A patient with cystic fibrosis comes complaining
of foul smelling stool. After a complete physical
examination and test results, you determine that
the patient has exocrine pancreatic insufficiency.
Weeks later, the patient still complains that the
smell is still there even after the enzymes you are
prescribing and after a decrease in dietary fat
intake, you opt to prescribe the patient a
medication. What is the mechanism of action on
the additional medication?
PPI
• Profoundly inhibit an ATPase located on
parietal cell membranes, thereby inhibiting
acid secretion
• Patient comes in complaining of queasiness
and a little discomfort. What medications
might you tell them to pick up over the
counter?
FOR SIMPLE N/V
• Minimal therapy
• OTC products
• Antacids and H2-receptor antagonist
(cimetidine) may provide relief through gastric
acid neutralization
• Patient comes into your office telling you that
their spouse decided to book a cruise despite
their motion sickness from it. You decide to
prescribe the patient a transdermal patch.
What type of receptor is the patch MOST
working on?
• Scopolamine is a strong muscarinic receptor
antagonist – better tolerated given TD – not as much
histamine effect with TD patch.
• An older physician explains to you that he
used to use a medication for post-operative
nausea and vomiting. He goes on to tell you
that the drug he used to use is only really used
in clinical trials these days. What adverse
effect might he discuss with you about this
drug?
Butyrophenones (Droperidol)
• Extreme sedation, potentially fatal QT
prolongation/torsade de pointes****,
extrapyramidal effects, hypotension
• A patient comes into the office complaining of
nausea and vomiting. You note in your
subjective part of your SOAP note a bunch of
medical conditions that seemingly correlate
with emesis. While you’re doing the physical,
you notice that the patient cannot stop
hiccupping. You decide to ask him about it
and find out, he’s been hiccupping for over a
month. What drug might you prescribe for
him?
• Chlorpromazine
• A patient comes into the Gibbs Center while
you’re doing one of your rotations. You note
that the patient is on a moderate emetic risk.
Aside from the corticosteroid, you prescribe
another medication for the patient. What is
the primary mechanism of action for this
medication? What about the secondary?
5-HT3 Antagonist
1. Primary: block presynaptic serotonin receptors
on the sensory vagal fibers of the gut wall
(afferent nerves)
2. Secondary: block serotonin receptors in the CTZ
and vomiting center
• For the previous question, 5-HT3 antagonists
were the class of medications. In that class of
medications, which drugs put a patient at a
risk for QT prolongation?
• QT prolongation with dolasetron (only PO rec for
CINV) and high-dose ondansetron
• The main function of metoclopramide is to
work on D2 receptors in the CTZ. This,
however, is not the only prokinetic effect of
the drug. Where else does this drug work on
to give a prokinetic effect of the GI tract?
– Serotonin activity
• 5-HT4 agonism (prokinetic)
• There is a 70 year old postmenopausal with a
history of atrial fibrillation patient that comes
into Gibbs now on a highly emetogenic
regimen. Not only do you give the patient the
typical dexamethasone and ondansteron, you
also give another drug to block a certain
receptor. What neuropeptide might you be
blocking at this receptor?
Neurokinin receptor antagonists
• MOA:
– Block neurokinin 1 (NK1) receptors in the STN
(afferent and efferent)
– NK1 is the preferred receptor for substance P****
• Indications:
– Used in combination with 5-HT3 receptors &
corticosteroids for the prevention of acute and
delayed CINV from highly emetogenic regimens – Also approved for prevention of PONV
• For the last patient, you realize that you have
to worry about the drug interactions with the
chemotherapy drugs given. The attending tells
you however that you should run a test due to
the patient’s extensive medication list. What is
the attending checking on the test?
Warfarin Intxn
• INR might be decreased.
• While on an internal medicine rotation, a
physician asks you about the prescriptions he is
writing as he is filling out his discharge
information for a patient who just had a surgery
by the famous Dr. Leong. He first tells you that he
is giving the patient a Norco (hydrocodoneacetaminophen) prescription and then asks what
medication he should prescribe along with it to
make sure the patient does not experience any
nausea. What medication do you suggest?
• Hydroxyzine
• A patient comes in with a history of motion
sickness and complains that the last
medication they received dried out their
mouth too much and left them feeling too
sleepy. What medication would you prescribe
in order to minimize this problem?
• Meclizine has minimal anticholinergic properties and
causes less sedation
• A woman in her first trimester comes into your
office and tells you that she’s been feeling the
effects of morning sickness on a daily basis. She’s
tried avoiding trigger foods and eats crackers
often to avoid and empty stomach, but nothing is
working. She then asks you for some
ondansetron because one of her friends had it
during her pregnancy. You then explain to her the
risks of using such a drug. What risks might those
be?
• Two-fold increase in the risk of congenital heart
defects and cleft palate in the first trimester
• For the previous patient, what is the FDA
pregnancy category for the drugs that you
prescribe the patients instead?
• Both pyridoxine and doxylamine is FDA
Pregnancy Category A