NBME 20 Omeprazole (NBME Answers)

Retired NBME 20 Answers

nbme20/Block 1/Question#24 (reveal difficulty score)
A 50-year-old man comes to the physician ...
Omeprazole 🔍 / 📺 / 🌳 / 📖
tags: pharm

+26 upvote downvote
submitted by ∗justgettinby(26)

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Itraconazole requires the acidic environment of the stomach to be absorbed. Omeprazole inhibits the H+/K+ pump of the stomach, thereby decreasing the acidity of the stomach. So when the patient takes Omeprazole and Itraconazole together, Itraconazole won't be absorbed into the body. That's why it has no effect.

It's recommended to take medications at least 2 hours prior to taking an antacid.

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necrotizingfasciitis Just adding support to the above explanation: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3671798/ +4

pakimd do all azoles or just itraconazole only requires an acidic environment to be absorbed? +2

chandlerbas just itraconazole and posaconazole +5

lilyo @chandlerbas, where did you find this information? I was looking over this on FA but they do not mention it and I would like a bit more information. Thanks! +5

chandlerbas haha no stress! the article above submitted by @necrotizingfasciitis does a descent job explaining it, however its not good enough, I looked into a bit more on uptodate but wasn't fruitful in my endeavours. goodluck! +

haozhier How are we supposed to know this!! It is not in UWORLD or FA right? +14

kevin Someone said it on here, since there was no CYP inducer of the answer choices, the only way to even think about an answer to this question was to just go with a less acidic environment from the PPI affecting absorption. It was simply the only reasonable answer choice, I don't think there's any way we were expected to know of this exact interaction prior +1

aoa05 Golan pharm book states the exact same thing. Cannot be given to patients with acholrhydria. +

j44n https://www.uspharmacist.com/article/the-fungus-among-us-an-antifungal-review +

+8 upvote downvote
submitted by nadhq(8)

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I highly doubt that writers of this question expect us to know the relation between itraconazole and PPI but rather if a patient has a multidrug regimen (including a PPI), if there is no p450 related stuff going and drug absorbtion is defective we should be suspicious of the PPIs. Like a general rule or something like that.

Otherwise, if they expect us to know the specific relation between the two... meh this question sucks really hard then.

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+1 upvote downvote
submitted by ∗stepwarrior(29)

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this is clearly another one of those trap questions for overthinkers

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+0 upvote downvote
submitted by ∗amy(4)

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Found this in uptodate: Omeprazole drug information, so it can go both ways.... "Itraconazole: Proton Pump Inhibitors may increase the serum concentration of Itraconazole. Proton Pump Inhibitors may decrease the serum concentration of Itraconazole. Management: Exposure to Tolsura brand itraconazole may be increased by PPIs; consider itraconazole dose reduction. Exposure to Sporanox brand itraconazole capsules may be decreased by PPIs. Give Sporanox brand itraconazole at least 2 hrs before or 2 hrs after PPIs Risk D: Consider therapy modification"

For ketoconazole, it did say PPI decreases its serum level

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+0 upvote downvote
submitted by andremosq(9)

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The encapsulated formulation of itraconazole has been associated with wide variability in plasma concentrations due to variability in absorption from the gastrointestinal (GI) tract.

Encapsulated itraconazole requires an acidic pH in the stomach for the proper dissolution and absorption in the duodenum (small intestine).

Proton pump inhibitor medications can increase the gastric pH and thereby decrease the dissolution of the capsule and the amount of itraconazole available for absorption from the GI tract for systemic delivery.

by:Anthony J. Busti, MD, PharmD, FNLA, FAHA

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-11 upvote downvote
submitted by ∗strugglebus(189)

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This a CYP 450 inhibitor (SICKFACES.COM); its the O.

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coccidioinmytitties Azoles, as a class, are CYP450 inhibitors [fungal > human; to prevent conversion of lanosterol to ergosterol]. Justget is correct- a ↓pH is needed for absorption and PPI/H2RA/antacids are contraindicated. +

-13 upvote downvote
submitted by ∗hayayah(1212)

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Add on to the other comment: SICKFACES.COM (when I Am drinking Grapefruit juice) is the mnemonic for remembering the CYP450 Inhibitors:

S odium valproate
I soniazid
C imetidine
K etoconazole
F luconazole
A cute alcohol abuse
C hloramphenicol
E rythromycin/clarithromycin
S ulfonamides
C iprofloxacin
O meprazole
M etronidazole
A miodarone
Grapefruit juice

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charcot_bouchard Its not a cytochrome question. IK because i go t it wrong +1

waterloo both azoles and PPI inhibit cytochrome P450. So one isn't causing the other's lack of effect. +9

stepwarrior Nope. Inhibiting CYP450 would enhance the effect of itraconazole, so that can't be the mechanism. +2

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