A 48-year-old woman with 2-year history of rheumatoid arthritis has not had sufficient relief with methotrexate alone. Her physician prescribes etanercept to help control her symptoms. How does etanercept work?

Correct Answer: D

Rationale: Etanercept, a TNF-α inhibitor, works by inhibiting TNF-α signaling , reducing RA inflammation. Substance P depletion , COX inhibition , and chemotaxis inhibition are unrelated. Arachidonic acid prevention (E) isn't its role. This targets a key RA cytokine.

Correct Answer: B

Rationale: Cyanocobalamin, or vitamin B12, is essential for red blood cell production and neurological function, and its deficiency directly leads to pernicious anemia, a condition characterized by large, immature red blood cells due to impaired DNA synthesis. This occurs because B12 is crucial for folate metabolism and erythropoiesis, and without it, anemia develops, often accompanied by neurological symptoms like numbness or tingling. Pellagra, however, results from niacin (vitamin B3) deficiency, manifesting as dermatitis, diarrhea, and dementia-unrelated to B12's role. Rickets stems from vitamin D deficiency, causing bone deformities due to poor calcium absorption, not a B12 issue. Scurvy arises from vitamin C deficiency, leading to collagen breakdown and symptoms like bleeding gums, distinct from B12's hematological effects. Pernicious anemia stands out as the correct outcome because B12 deficiency disrupts bone marrow function, and it often requires pharmacotherapy, such as B12 injections, especially if absorption is impaired (e.g., due to lack of intrinsic factor). This specificity eliminates other conditions, highlighting B12's unique role in blood and nerve health.

Correct Answer: D

Rationale: Sinusitis treatment often involves OTC antihistamines. Diphenhydramine , an H1 antihistamine, causes sedation, explaining the student's sleepiness during the exam. Doxycycline , an antibiotic, doesn't sedate. Doxylamine , another sedating antihistamine, is possible but less commonly linked to sinusitis OTC use. Doxazosin , an α-blocker, isn't for sinusitis. Hydroxyzine (E) sedates but is prescription-based. Diphenhydramine's widespread OTC availability and drowsiness side effect fit the scenario, impacting the student's performance.

Correct Answer: D

Rationale: Metoprolol selectively blocks beta-1 adrenergic receptors, reducing heart rate and cardiac output.

Correct Answer: B

Rationale: Omeprazole, a proton pump inhibitor (PPI), is most effective when taken 30 minutes before meals. This allows the medication to inhibit proton pumps during meal-stimulated acid production. Taking it after (A) or with meals (C) reduces its effectiveness. While it can be taken without regard to meals (D), taking it before meals is optimal.