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Chapter 18: Prostaglandins & Other Eicosanoids

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A 50-year-old woman with moderately severe arthritis has been treated with nonsteroidal anti-inflammatory drugs for 6 mo. She now complains of heartburn and indigestion. You give her a prescription for a drug to be taken along with the anti-inflammatory agent, but 2 d later she calls the office complaining that your last prescription has caused severe diarrhea. Which of the following is most likely to be associated with increased gastrointestinal motility and diarrhea?

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(A) Aspirin

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(B) Famotidine

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(C) Leukotriene LTB4

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(D) Misoprostol

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(E) Zileuton

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Aspirin and zileuton rarely cause diarrhea. LTB4 is a chemotactic factor. Famotidine is an H2 blocker that does not cause diarrhea (Chapter 16). The answer is D.

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Which of the following drugs inhibits thromboxane synthesis much more effectively than prostacyclin synthesis?

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(A) Aspirin

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(B) Hydrocortisone

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(C) Ibuprofen

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(D) Indomethacin

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(E) Zileuton

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Hydrocortisone and other corticosteroids inhibit phospholipase. Ibuprofen and indomethacin inhibit cyclooxygenase reversibly, whereas zileuton inhibits lipoxygenase. Because aspirin inhibits cyclooxygenase irreversibly, its action is more effective in platelets, which lack the ability to synthesize new enzyme, than in the endothelium. The answer is A.

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A 57-year-old man has severe pulmonary hypertension and right ventricular hypertrophy. Which of the following agents causes vasodilation and may be useful in pulmonary hypertension?

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(A) Angiotensin II

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(B) Ergotamine

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(C) Prostaglandin PGF

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(D) Prostacyclin

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(E) Thromboxane

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Prostacyclin (PGI2) is a very potent vasodilator. All the other choices in the list are vasoconstrictors. The answer is D.

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A 19-year-old woman complains of severe dysmenorrhea. A uterine stimulant derived from membrane lipid in the endometrium is

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(A) Angiotensin II

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(B) Oxytocin

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(C) Prostacyclin (PGI2)

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(D) Prostaglandin PGF

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(E) Serotonin

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Although serotonin and, in some species, histamine may cause uterine stimulation, these substances are not derived from membrane lipid. Similarly, oxytocin ...

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