Материал: 2016_Kaplan_USMLE_Step_1_Lecture_Notes_Pharmacology

Chapter 9 λ Inflammatory Disorder Drug List and Practice Questions

11.Following an overdose of an over-the-counter drug, a young college student

has marked gastrointestinal distress and is lethargic and confused, with an

elevated body temperature. Lab analysis of blood reveals: pCO2, ↓ HCO3–, ↓ K+, and an anion gap acidosis. The most likely cause of these signs and symptoms is a toxic dose of

A.acetaminophen

B.acetylsalicylic acid

C.diphenhydramine

D.pseudoephedrine

E.naproxen

12.Which statement below is accurate regarding aspirin overdose?

A.N-acetylcysteine should be given immediately

B.The metabolism rate of aspirin is first-order

C.Elimination rate is directly proportional to plasma concentration.

D.Increasing urinary pH would be beneficial

E.Plasma concentrations decrease exponentially with time.

13.Which one of the following antiinflammatory drugs used in rheumatoid arthritis can bind directly tumor necrosis factor?

A.Etanercept

B.Sulfasalazine

C.Prednisone

D.Celecoxib

E.Penicillamine

14.When used in the management of asthma, glucocorticoids are likely to cause

A.hypoglycemia

B.decreases in blood pressure

C.anabolic actions in wound healing

D.oral thrush

E.sedation

15.A reasonable explanation for the therapeutic effects of ibuprofen or naproxen in primary dysmenorrhea is that these drugs

A.↓ PGE2 and PGF2α

B.selectively inhibit COX 2

C.↓ LTB4

D.inhibit PLA2

E.PI2

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Section VI λ Drugs for Inflammatory and Related Disorders

16.When a patient is started on an appropriate drug for chronic gout it is observed that that the plasma levels of uric acid decrease while the urine levels of uric acid increase. What drug was the patient treated with?

A.Allopurinol

B.Acetylsalicylic acid

C.Indomethacin

D.Colchicine

E.Probenecid

17.The plasma levels of ketoconazole are lower than normal following its oral absorption in patients treated with lansoprazole. What is the reason for this?

A.The induction of enzymes that metabolize ketoconazole

B.Ketoconazole requires an acid environment for its oral absorption

C.Lansoprazole binds acidic drugs in the gastrointestinal tract

D.Increased gastrointestinal transit time because of the prokinetic effects of lansoprazole

E.Competition for transport mechanisms in the gastrointestinal tract

18.Cromolyn useful in many patients with asthma because it

A.inhibits COX 2

B.blocks adenosine receptors in bronchiolar smooth muscle

C.prevents antigen-induced degranulation of mast cells

D.inhibits phosphodiesterase

E.↓ mRNA for IL-2

19.Which one of the following is able to effectively lower intraocular pressure?

A.Latanoprost

B.Ergonovine

C.Atropine

D.Terbutaline

E.Morphine

20.Cancer patients being treated with 6-MP may require a dosage adjustment if they are concurrently treated for which of the following?

A.Constipation

B.Malaria

C.Chronic gout

D.Arthritis

E.Headache

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Chapter 9 λ Inflammatory Disorder Drug List and Practice Questions

21.Constipation is highly unlikely to occur with the use of which of the following?

A.Diphenhydramine

B.Docusate

C.Promethazine

D.Loperamide

E.Scopolamine

22.A 2-year-old child is brought into the emergency department in convulsions. According to her mother, she had ingested most of a bottle of “sleeping pills,” an over-the-counter preparation. What do the sleeping pills she ingested probably contain?

A.Caffeine

B.Chlorpromazine

C.Diphenhydramine

D.Meperidine

E.Temazepam

23.In a person who regularly consumes ethanol daily, the potential for hepatotoxicity due to acetaminophen is greater than normal. What is the most likely explanation for this?

A.Cirrhosis of the liver

B.Ethanol inhibits the metabolism of acetaminophen

C.Most beer drinkers are smokers, and nicotine sensitizes the liver to toxins

D.Nutritional deficiency

E.Ethanol induces P450 enzymes that form a toxic metabolite

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Section VI λ Drugs for Inflammatory and Related Disorders

Answers

1.Answer: D. Misoprostol is a prostaglandin analog indicated for specific use in NSAID-induced ulcers since NSAIDs inhibit the synthesis of protective GI prostaglandins. Other answer choices may be of benefit in this type of ulcer but none are selectively used for NSAIDs.

2.Answer: A. Acetaminophen is metabolized primarily by glucuronidation to an inactive metabolite. A minor pathway for metabolism involves cytochrome P450 conversion of acetaminophen to a reactive metabolite that damages the liver. The reactive metabolite is rapidly inactivated normally by glutathione. Prompt administration of N-acetylcysteine is useful because, like glutathione, it supplies sulfhydryl groups to bind the reactive species.

3.Answer: C. Various glucocorticoids have different abilities to affect the mineralocorticoid receptor to cause sodium and water retention (an aldosterone-like effect). Generally, the more potent the glucocorticoid, the less likely it is to have an aldosterone effect. Cortisol is a weak glucorcorticoid that is equally effective at stimulating mineralocorticoid receptors and thus has sodium and water retention as a property.

4.Answer: C. Ocular toxicity is characteristic of chloroquine and hydroxychloroquine. Corneal deposits are reversible, but retinal pigmentation can ultimately lead to blindness. Patients will complain about gastrointestinal distress, visual dysfunction, ringing in the ears (note that tinnitus also occurs in salicylism), and “itchy skin.” Hydroxychloroquine also promotes oxidative stress that can lead to hemolysis in G6PD deficiency. DMARDs include gold salts (e.g., auranofin), methotrexate, and etanercept, but thioridazine is a phenothiazine used as an antipsychotic; it lacks an antiinflammatory effect, but does cause retinal pigmentation.

5.Answer: D. The usual choice for pollen-induced allergies would be an H1 antagonist. Of the two listed, loratadine would be the best choice in this case because it does not cross the blood–brain barrier and is nonsedating; hydroxyzine is an effective CNS depressant used for preoperative sedation. Cromolyn (not listed) can also be used in allergic rhinitis and is also nonsedating. Betamethasone, a potent antiinflammatory steroid, is less effective than antihistamines in this situation and would cause more serious side effects. Metoclopramide is a DA-receptor antagonist and prokinetic used as an antiemetic and in GERD. Cimetidine is the prototype H2 antagonist used in gastrointestinal ulcers.

6.Answer: D. Cimetidine is an inhibitor of the hepatic cytochrome P450 isoform that metabolizes warfarin, consequently decreasing its clearance and thus increasing its elimination half-life. The hepatic metabolism of many other drugs can be inhibited by cimetidine, possibly necessitating dose reductions to avoid toxicity, including beta blockers, isoniazid, procainamide, metronidazole, tricyclic antidepressants, and phenytoin.

7.Answer: B. It is important to be able to match the serotonin drugs with their respective receptors. The “triptans” used in migraine headaches are agonists at the 5HT1D receptor.

8.Answer: D. Zileuton blocks the enzyme 5-lipoxygenase which prevents the formation of leukotrienes. This drug is one of many adjuncts available in asthma. Montelukast blocks leukotriene receptors but has no effect on the synthesis of leukotrienes.

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Chapter 9 λ Inflammatory Disorder Drug List and Practice Questions

9.Answer: C. Meclizine is a first-generation antihistamine that effectively penetrates the CNS. Like all first-generation drugs it also blocks muscarinic

receptors. Blocking the H1 and muscarinic receptors are beneficial in motion sickness and nausea and vomiting in pregnancy. Second-generation drugs like loratidine and fexofenadine don’t effectively penetrate the CNS and are of no benefit in these conditions.

10.Answer: A. During fetal development, the ductus arteriosus is kept open by

prostaglandins. For temporary maintenance of patency in the infant, the PGE1 analog alprostadil is used. Closure of the ductus in the infant can often be accomplished by intravenous indomethacin, which ↓ PG synthesis by inhibiting COX. Epoprostenol is a prostacyclin analog used in primary pulmonary hypertension.

11.Answer: B. If the patient had been able to mention tinnitus, this would be a classic case of aspirin poisoning. At high salicylate blood levels, the combination of effects leading to respiratory depression (respiratory acidosis) and metabolic acidosis results in the observed pH and electrolyte changes, the anion gap (a marker for acidosis), and hyperthermia.

12.Answer: D. Back to basic principles. Zero-order elimination means that plasma levels of a drug decrease linearly with time. This occurs with ASA at toxic

doses, with phenytoin at high therapeutic doses, and with ethanol at all doses. Enzymes that metabolize ASA are saturated at high plasma levels → constant rate of metabolism = zero-order kinetics. Remember that application of the Henderson-Hasselbalch principle can be important in drug overdose situa-

tions. In the case of aspirin, a weak acid, urinary alkalinization favors ionization of the drug →↓ tubular reabsorption → renal elimination. N-acetylcysteine is the antidote for acetaminophen.

13.Answer: A. Etanercept binds directly to tumor necrosis factor (TNF), resulting in the inactivation of this cytokine, which plays a major role in a number of inflammatory disorders, including Crohn disease and rheumatoid arthritis. In the synovium, TNF recruits inflammatory cells and leads to angiogenesis and joint destruction. Infliximab, a monoclonal antibody, also inactivates TNF.

14.Answer: D. Most often glucocorticoids are used in the treatment of asthma not controlled by a beta-2 agonist inhaler alone. The glucocorticoid is often given by metered dose inhaler when enhances the risk of oral candidiasis (thrush). This can be avoided by rinsing the mouth thoroughly and by using spacers. All of the other effects listed are “opposites,” so anticipate possible hyperglycemia, hypertension, decreased wound healing, and CNS excitatory effects that have been interpreted as psychosis.

15.Answer: A. PGE2 and PGF2α both increase in primary dysmenorrhea, and the therapeutic effects of NSAIDs appear to be due to inhibition of the synthesis of these prostaglandins. Both ibuprofen and naproxen are nonselective COX inhibi-

tors that can inhibit the synthesis of prostacyclin (PGI2). NSAIDs do not inhibit phospholipase A2, and they do not decrease leukotrienes.

16.Answer: E. In chronic gout, the strategy is to decrease uric acid formation from purines by inhibiting xanthine oxidase with allopurinol or increasing urate elimination with uricosurics such as probenecid. Probenecid blocks the tubular reabsorption of uric acid which lowers blood levels of uric acid but results in uricosuria. Colchicine and NSAIDs are less effective and cause more side effects when used in chronic gout. There are preferred In acute gout attacks. Although ASA is uricosuric at antiinflammatory doses, its toxicity makes the drug a poor choice.

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