new_n_lost
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A 70-year-old man with a history of atrial fibrillation is started on an oral anticoagulant. His prothrombin time is monitored on a regular basis. A few months into his therapy, he begins treatment for a duodenal ulcer and he develops symptoms of a bleeding diathesis.
Which of the following ulcer medications is most likely responsible for this change in his hemostatic
status?
A. Cimetidine
B. Famotidine
C. Misoprostol
D. Omeprazole
E. Ranitidine
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| mytime
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A. P450
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| keepgoing
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yes cimetidine..no doubt
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| angel^Doctor
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A --> IHNIBITS P 45O
its VERY IMP to keep in mind that this drug also cause GYNACOMASTIA
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| new_n_lost
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mytime wrote:
A. P450
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| new_n_lost
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The correct answer is A.
Warfarin is the oral anticoagulant the patient was most likely taking. This drug is commonly prescribed to patients with atrial fibrillation to prevent the formation of atrial thrombi. Warfarin increases prothrombin time (PT) because it interferes with the synthesis of the vitamin K clotting factors of the liver (II, VII, IX, and X) and therefore necessitates regular monitoring of the PT.
Cimetidine is an H2-blocker that inhibits hepatic enzymes, including those that metabolize warfarin. Consequently, coadministration of warfarin and cimetidine results in enhanced warfarin activity, producing pronounced anticoagulation and the bleeding diathesis in the patient in question. Cimetidine has one of the worst side effect profiles of all the H2-blockers and may also result in gynecomastia in men.
Famotidine (choice B) is an H2-blocker that does not affect liver metabolism.
Misoprostol (choice C) is a prostaglandin E1 analog used in peptic ulcer disease. It does not affect hepatic metabolism.
Omeprazole (choice D) is a proton-pump inhibitor used to decrease acid production in patients with peptic ulcer disease or reflux. It does not affect drug metabolism by the liver.
Ranitidine (choice E) is another H2-blocker. It does not inhibit liver enzymes as strongly as cimetidine does.
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| tompat
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D'oh!
i wud say omeprazole. cuz doc in ulcer disease is h+ pump blockers and omez also inhibits p450 system.
no doubt cimetidine does same but if u want to prescribe anti ulcer which one u wud select?
please do reply
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| new_n_lost
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tompat wrote:
D'oh!
i wud say omeprazole. cuz doc in ulcer disease is h+ pump blockers and omez also inhibits p450 system.
Do u have any reference to that cos i have Katzung and it says nothing abt it Being an inhibitor of P450 although its metabolized by it.
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| tompat
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i guess kaplan . not sure thou
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| amritt786
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lipponcot state that omprazole inhibit oxidation of warfarin, phenytoin but i dont think this will effect much to cause clincal drug interaction
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| tompat
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come on guys, kaplan mentions it clearly that its(omez) a p450 inhibitor.
one has to know cold these inhibitors and simulators.
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| new_n_lost
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tompat wrote:
come on guys, kaplan mentions it clearly that its(omez) a p450 inhibitor.
one has to know cold these inhibitors and simulators.
I agree on ur point that Kaplan mentions it but its in high doses. Its not a very potent inhibitor of P450.
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| tompat
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thanks. but where is it given that omez does it in it's high dosage?
further ain't cimetidine rarely prescribed now a days?
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