Top 200 drugs and key interactions. Original NAPLEX-style single-best-answer questions on the most commonly dispensed drugs: mechanism, indications, adverse effects, interactions, dosing, counselling, special populations and pharmacy calculations. Every question has a concise explanation and public references (FDA labels via DailyMed, NCBI Bookshelf, FDA). Aligned to the NABP NAPLEX Content Outline domains (Foundational Knowledge, Medication Use Process, Person-Centered Assessment and Treatment Planning). Educational use only; not an official NABP product.
Apixaban prevents stroke in non-valvular atrial fibrillation by which mechanism?
Inhibition of vitamin K epoxide reductase
Inhibition of glycoprotein IIb/IIIa
Direct inhibition of thrombin (factor IIa)
Direct, selective inhibition of free and clot-bound factor Xa
Binding antithrombin to accelerate factor Xa inactivation
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Richtige Antwort: D. Direct, selective inhibition of free and clot-bound factor Xa
Apixaban, rivaroxaban and edoxaban are direct factor Xa inhibitors that do not require antithrombin. Dabigatran is the oral direct thrombin inhibitor, and heparins act through antithrombin.
A patient who takes atorvastatin drinks large amounts of grapefruit juice. What is the pharmacist's best advice?
Limit grapefruit juice because intestinal CYP3A4 inhibition can raise atorvastatin levels
Grapefruit juice lowers atorvastatin efficacy, so take double the dose
Grapefruit juice only matters with penicillins
Grapefruit has no interactions with any drug
Take the statin only in the morning to avoid the effect
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Richtige Antwort: A. Limit grapefruit juice because intestinal CYP3A4 inhibition can raise atorvastatin levels
Grapefruit juice irreversibly inhibits intestinal CYP3A4; the effect is greater for simvastatin and lovastatin than atorvastatin, but large quantities (over 1.2 L per day) may raise exposure. Pravastatin and rosuvastatin are unaffected.
A patient on simvastatin reports new diffuse muscle pain and dark urine. What is the most appropriate action?
Add ezetimibe and continue
Stop the statin and obtain creatine kinase and renal function urgently
Take the statin at night only
Continue and recheck in 6 months
Double the dose
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Richtige Antwort: B. Stop the statin and obtain creatine kinase and renal function urgently
Statin-associated rhabdomyolysis presents with myalgia, weakness and myoglobinuria and can cause acute kidney injury. Risk factors include high dose, interacting drugs, hypothyroidism, renal disease and older age.
What INR range is typical for a patient on warfarin for non-valvular AF or VTE?
1.0 to 1.5
4.0 to 5.0
2.0 to 3.0
3.5 to 4.5
0.8 to 1.2
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Richtige Antwort: C. 2.0 to 3.0
A target INR of 2.5 (range 2-3) applies to most indications; mechanical mitral valves generally target 3 (2.5-3.5). Time in therapeutic range correlates with outcomes.