NAPLEX Quiz: Indications And Dosing Regimens

What this quiz covers

This quiz focuses on Indications And Dosing Regimens, giving you a quick way to practice the rules, question types, and explanations that matter most for NAPLEX.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

Question 1

1. Lisinopril (correct answer)
2. Hydralazine
3. Propranolol
4. Clonidine

Explanation: This question tests the appropriate medication for renal protection in diabetic kidney disease. Key patient-specific factors include albuminuria 220 mg/g, type 2 diabetes, and BP 138/84 mmHg near goal. The best choice is lisinopril, as ADA guidelines recommend ACE inhibitors to slow progression via antiproteinuric effects. Option B lacks renoprotection; option C may worsen; option D is central-acting. These distractors ignore evidence for RAAS inhibition. A pearl is to target ACR <30 mg/g with therapy. Framework: Prioritize ACEI/ARB in proteinuric DKD regardless of BP.

Question 2

1. Apixaban 10 mg PO twice daily for 7 days, then 5 mg PO twice daily
2. Apixaban 2.5 mg PO twice daily
3. Apixaban 5 mg PO twice daily (correct answer)
4. Apixaban 2.5 mg PO once daily

Explanation: This question tests appropriate apixaban dosing for stroke prevention in nonvalvular atrial fibrillation with renal impairment. Key patient-specific factors include severe renal impairment (CrCl 22 mL/min), age 58 years, weight 74 kg, and absence of other dose-reduction criteria. Apixaban 5 mg PO twice daily is correct because the patient meets only ONE of the three criteria for dose reduction (age ≥80 years, weight ≤60 kg, or SCr ≥1.5 mg/dL) - her SCr is 2.6 mg/dL. Apixaban requires dose reduction to 2.5 mg twice daily only when TWO or more criteria are met. Choice A (10 mg twice daily for 7 days) is the treatment dose for acute VTE, not atrial fibrillation stroke prevention. Choices B and D represent inappropriate dose reductions since only one criterion is met. The clinical pearl is that apixaban dose reduction for atrial fibrillation requires meeting at least TWO of three specific criteria, unlike other DOACs which may have different renal cutoffs, and severe renal impairment alone (even with CrCl <25 mL/min) does not automatically mandate dose reduction if other criteria are absent.

Question 3

1. Amoxicillin/clavulanate requires renal dose reduction because CrCl is < 60 mL/min
2. Warfarin dose may need adjustment/closer monitoring due to interaction increasing INR risk (correct answer)
3. Sertraline dose must be reduced due to increased bleeding risk with warfarin
4. Levothyroxine must be held during antibiotic therapy to prevent reduced absorption

Explanation: This question tests recognition of drug interactions requiring monitoring or dose adjustment. The key interaction is between amoxicillin/clavulanate and warfarin, which can increase INR and bleeding risk through multiple mechanisms including disruption of gut flora that produce vitamin K. Warfarin dose may need adjustment and closer INR monitoring is required during and after antibiotic therapy, making choice B correct. Choice A is incorrect because amoxicillin/clavulanate does not require renal dose adjustment until CrCl <30 mL/min, and this patient's CrCl is approximately 75 mL/min (using Cockcroft-Gault: (140-63)×82×0.85/(72×0.9)). Choice C is incorrect as sertraline dose adjustment is not required solely due to concurrent warfarin use, though both can increase bleeding risk. Choice D is incorrect because levothyroxine does not need to be held during antibiotic therapy; any interaction affecting absorption can be managed by consistent administration timing. The clinical pearl is that many antibiotics, including amoxicillin/clavulanate, can potentiate warfarin's effect requiring increased INR monitoring frequency during and for several days after antibiotic completion.

Question 4

1. Ciprofloxacin 500 mg PO twice daily for 7 days (correct answer)
2. Nitrofurantoin monohydrate/macrocrystals 100 mg PO twice daily for 5 days
3. Trimethoprim-sulfamethoxazole DS 1 tablet PO twice daily for 3 days
4. Doxycycline 100 mg PO twice daily for 7 days

Explanation: This question tests the appropriate empiric antibiotic selection for complicated urinary tract infection (UTI) in males. Key patient-specific factors include male gender (all UTIs in males are considered complicated), sulfonamide allergy (eliminating trimethoprim-sulfamethoxazole), and reduced renal function (CrCl 45 mL/min, which contraindicates nitrofurantoin). Ciprofloxacin 500 mg PO twice daily for 7 days is the best choice as it provides appropriate coverage for complicated UTI pathogens, achieves adequate urinary concentrations despite moderate renal impairment, and avoids the patient's sulfa allergy. Nitrofurantoin (choice B) is contraindicated when CrCl <60 mL/min due to inadequate urinary drug concentrations and increased toxicity risk. Trimethoprim-sulfamethoxazole (choice C) is contraindicated due to the patient's sulfonamide allergy history of hives. Doxycycline (choice D) has poor urinary penetration and is not recommended for UTI treatment. The clinical pearl is that all UTIs in males are considered complicated and require longer treatment durations (7-14 days) compared to uncomplicated UTIs in females, and renal function must be assessed before selecting antibiotics like nitrofurantoin.

Question 5

1. Venlafaxine XR 37.5 mg PO daily (correct answer)
2. Venlafaxine XR 225 mg PO daily
3. Venlafaxine XR 150 mg PO twice daily
4. Venlafaxine IR 300 mg PO daily starting dose

Explanation: This question tests the appropriate initial dosing for venlafaxine XR in major depressive disorder. Key patient-specific factors include inadequate response to sertraline, normal labs, and adult status. The best choice is venlafaxine XR 37.5 mg PO daily, as APA guidelines and labeling recommend starting low and titrating to minimize side effects like hypertension. Option B starts too high; option C exceeds daily max; option D uses IR form incorrectly. These distractors ignore titration needs. A pearl is to monitor BP during SNRI initiation. Framework: Escalate antidepressants gradually, assessing response every 4-6 weeks.

Question 6

1. Continue warfarin 5 mg daily and recheck INR in 4 weeks
2. Hold 1–2 doses of warfarin and resume at a lower weekly dose; recheck INR within about 1 week (correct answer)
3. Administer vitamin K 10 mg IV and continue warfarin at same dose
4. Stop warfarin permanently and start aspirin 325 mg daily

Explanation: This question tests appropriate management of supratherapeutic INR on warfarin without bleeding. Key patient-specific factors include INR 4.8 (goal 2-3), no bleeding, stable Hgb, and amiodarone interaction potentiating warfarin. The best choice is to hold 1-2 doses and resume at lower weekly dose with recheck in 1 week, per ACCP guidelines for minor elevations to safely lower INR without over-correction. Option A ignores elevation, risking bleed; option C uses vitamin K unnecessarily for asymptomatic cases; option D stops permanently, inappropriate for AF. These distractors over- or under-react to INR. A pearl is to adjust warfarin by 10-20% weekly for deviations. Framework: Use INR trends and factors like drugs/diet for dose decisions.

Question 7

1. Apixaban 10 mg PO twice daily for 7 days, then 5 mg PO twice daily
2. Apixaban 2.5 mg PO twice daily
3. Apixaban 5 mg PO twice daily (correct answer)
4. Apixaban 5 mg PO once daily

Explanation: This question tests the appropriate dosing regimen for apixaban in stroke prevention for nonvalvular atrial fibrillation (NVAF). Key patient-specific factors include age 59 years, weight 70 kg, SCr 1.6 mg/dL with CrCl 28 mL/min, and concomitant amiodarone, a P-gp inhibitor that may increase apixaban exposure. The best choice is apixaban 5 mg PO twice daily, as ARISTOTLE trial guidelines and labeling recommend the standard dose unless two of three criteria (age ≥80, weight ≤60 kg, SCr ≥1.5 mg/dL) are met for dose reduction, and here only one criterion (SCr) applies despite renal impairment and drug interaction. Option A is the loading regimen for VTE treatment, not indicated for NVAF; option B applies the reduced dose incorrectly without meeting criteria; option D halves the frequency inappropriately, risking subtherapeutic levels. These distractors reflect errors in applying dose reduction criteria or confusing indications. A transferable pearl is to use the ABC criteria (age, body weight, creatinine) for apixaban dosing in NVAF, avoiding automatic reductions for isolated factors. For similar anticoagulants, always check for drug interactions via P-gp/CYP3A4 and adjust per product labeling.

Question 8

1. Doxycycline 100 mg PO twice daily for 5–7 days (correct answer)
2. Doxycycline 50 mg PO twice daily for 3 days
3. Doxycycline 200 mg PO once daily for 14 days
4. Doxycycline 100 mg PO once daily for 3 days

Explanation: This question tests the appropriate dosing regimen for doxycycline in outpatient community-acquired pneumonia (CAP). Key patient-specific factors include age 71 years, penicillin allergy, eGFR 58 mL/min/1.73 m² allowing standard dosing, and non-ICU status. The best choice is doxycycline 100 mg PO twice daily for 5-7 days, as IDSA/ATS guidelines endorse this for outpatient CAP in adults with beta-lactam allergies, providing coverage for atypical pathogens. Option B under-doses and shortens duration, risking failure; option C uses excessive dose and duration; option D reduces frequency inappropriately. These distractors reflect errors in duration and frequency for respiratory infections. A pearl is to tailor CAP therapy duration to clinical response, minimum 5 days. Framework: Consider comorbidities, allergies, and local resistance when selecting antibiotics for CAP.

Question 9

1. Nitrofurantoin 50 mg PO every 6 hours for 3 days
2. Nitrofurantoin 100 mg PO twice daily for 5 days (correct answer)
3. Nitrofurantoin 100 mg PO twice daily for 10–14 days
4. Nitrofurantoin 100 mg PO once daily for 5 days

Explanation: This question tests the appropriate dosing regimen for nitrofurantoin in the treatment of uncomplicated urinary tract infection (UTI) in a male patient. Key patient-specific factors include age 67 years, male gender, eGFR 38 mL/min/1.73 m² indicating moderate renal impairment, and allergy to TMP-SMX limiting alternative options. The best choice is nitrofurantoin 100 mg PO twice daily for 5 days, as IDSA guidelines recommend this regimen for uncomplicated cystitis in adults when susceptibility is likely and renal function permits, with evidence supporting efficacy in males for 5-7 days despite traditional views of male UTIs as complicated. Option A uses a lower dose and shorter duration more suited for older formulations or pediatric use, making it suboptimal for efficacy; option C extends to 10-14 days, which is reserved for complicated UTIs or pyelonephritis; option D employs a prophylactic dose inadequate for acute treatment. These distractors highlight misconceptions about duration in uncomplicated vs. complicated infections and formulation-specific dosing. A clinical pearl is to always assess renal function before nitrofurantoin use, avoiding it if CrCl <30 mL/min due to risk of subtherapeutic levels and toxicity. For similar decisions, calculate eGFR and consider gender-specific UTI classification per AUA guidelines to guide duration.

Question 10

1. Chlorthalidone 12.5 mg PO daily (correct answer)
2. Chlorthalidone 100 mg PO daily
3. Chlorthalidone 50 mg PO twice daily
4. Chlorthalidone 2.5 mg PO daily

Explanation: This question tests the appropriate initial dosing for chlorthalidone in hypertension. Key patient-specific factors include new diagnosis, normal electrolytes/renal function, and BP 152/94 mmHg requiring therapy. The best choice is chlorthalidone 12.5 mg PO daily, as ACC/AHA guidelines recommend starting low (12.5-25 mg) for thiazides to minimize electrolyte disturbances while controlling BP. Option B overdoses at 100 mg; option C uses excessive frequency; option D under-doses at 2.5 mg. These distractors misapply dosing ranges. A pearl is to monitor potassium and renal function post-initiation. Framework: Titrate antihypertensives based on BP response and tolerability.

Question 11

1. Prednisone 40–60 mg PO daily for 5–7 days (correct answer)
2. Prednisone 5 mg PO daily indefinitely
3. Prednisone 120 mg PO once, then stop
4. Prednisone 10 mg PO every other day for 1 month

Explanation: This question tests the appropriate dosing regimen for oral prednisone in acute asthma exacerbation. Key patient-specific factors include adult status, outpatient management, and normal labs allowing standard therapy. The best choice is prednisone 40-60 mg PO daily for 5-7 days, as GINA guidelines recommend this short burst for adults to resolve inflammation without taper. Option B is low-dose chronic; option C is single high dose; option D alternates incorrectly. These distractors misapply duration/intensity. A pearl is to avoid prolonged courses to minimize side effects. Framework: Base corticosteroid dosing on severity and response in respiratory flares.

Question 12

1. 10 units SC once daily (correct answer)
2. 0.8 units/kg/day SC divided twice daily
3. 50 units SC once daily starting dose for all patients
4. 0.3 units/kg SC with each meal

Explanation: This question tests the appropriate initial dosing for basal insulin glargine in type 2 diabetes. Key patient-specific factors include weight 86 kg, A1c 10.2%, and fasting glucose 220 mg/dL with normal renal function. The best choice is 10 units SC once daily, as ADA guidelines recommend conservative starting (10 units or 0.1-0.2 units/kg) to minimize hypoglycemia, titrating by glucose. Option B is for total daily insulin; option C over-doses; option D is prandial. These distractors confuse basal vs. total dosing. A pearl is to titrate by 2-4 units every 3 days. Framework: Calculate starting dose by weight but start low in elderly.

Question 13

1. Severe hepatic impairment (Child-Pugh C) (correct answer)
2. Body weight 75 kg requires higher starting doses
3. Normal serum creatinine mandates avoidance of all hypnotics
4. Use of lactulose requires doubling hypnotic doses due to diarrhea

Explanation: This question tests factors requiring dose adjustment for sedative-hypnotics in insomnia. Key patient-specific factors include Child-Pugh C cirrhosis with elevated bilirubin/INR and low albumin, impairing metabolism. The best choice is severe hepatic impairment necessitating lower doses or avoidance, as guidelines recommend caution with hypnotics like zolpidem (start 5 mg) to prevent excessive sedation. Option B misapplies weight; option C ignores relevance; option D confuses lactulose effects. These distractors overlook pharmacokinetics. A pearl is to use Child-Pugh score for dosing in liver disease. Framework: Adjust for organ function in CNS drugs to avoid toxicity.

Question 14

1. Meningococcal conjugate (MenACWY) booster if not received at age 16 (correct answer)
2. Zoster recombinant vaccine (Shingrix) 2-dose series
3. Pneumococcal PCV20 single dose
4. RSV vaccine single dose

Explanation: This question tests the appropriate vaccine indication based on age and risk factors. Key patient-specific factors include age 19 years, dormitory living increasing meningococcal risk, and incomplete vaccination history. The best choice is meningococcal conjugate (MenACWY) booster if not received at 16, as CDC recommends for adolescents/young adults in high-risk settings like colleges. Option B is for age ≥50; option C for ≥65 or risk; option D similarly age-based. These distractors confuse age/risk indications. A pearl is to verify adolescent boosters for college entry. Framework: Assess lifestyle risks for vaccine recommendations.

Question 15

1. Atovaquone/proguanil 250/100 mg PO daily (correct answer)
2. Chloroquine 500 mg base PO weekly
3. Oseltamivir 75 mg PO daily
4. Acyclovir 400 mg PO twice daily

Explanation: This question tests the appropriate medication for malaria prophylaxis in chloroquine-resistant areas. Key patient-specific factors include travel to P. falciparum region, non-pregnant status, and normal labs. The best choice is atovaquone/proguanil 250/100 mg PO daily, as CDC guidelines recommend it for resistant areas, starting 1-2 days before travel. Option B is ineffective due to resistance; option C is for influenza; option D for herpes. These distractors confuse prophylaxis indications. A pearl is to continue prophylaxis post-travel per agent. Framework: Select based on destination resistance and patient factors.

Question 16

1. Start gabapentin at a reduced dose/frequency due to CrCl 25 mL/min and titrate as tolerated (correct answer)
2. Start gabapentin 900 mg PO three times daily regardless of renal function
3. Start gabapentin 600 mg PO every 4 hours PRN pain
4. Avoid gabapentin only because of age; renal function does not affect dosing

Explanation: This question tests the appropriate initial dosing approach for gabapentin in postherpetic neuralgia. Key patient-specific factors include age 83 years, low weight 50 kg, and CrCl 25 mL/min requiring renal adjustment. The best choice is to start at reduced dose/frequency and titrate, as guidelines recommend 100-300 mg daily in severe impairment to avoid sedation/accumulation. Option B ignores renal function; option C uses PRN incorrectly; option D dismisses renal impact. These distractors overlook adjustments. A pearl is to calculate CrCl for renally cleared drugs in elderly. Framework: Titrate neuromodulators slowly, monitoring CNS effects.

Question 17

1. Take doxycycline at the same time as calcium to reduce GI upset
2. Separate doxycycline and calcium carbonate by at least 2 hours (correct answer)
3. Crush doxycycline tablets and mix with milk for better absorption
4. Take doxycycline only with antacids to prevent esophagitis

Explanation: This question tests counseling on administration to avoid drug interactions with doxycycline. Key patient-specific factors include use of calcium carbonate, which chelates tetracyclines, and normal labs allowing standard therapy. The best choice is to separate doxycycline and calcium by at least 2 hours, as guidelines recommend staggering divalent cations to prevent reduced absorption and efficacy. Option A promotes co-administration, worsening interaction; option C suggests dairy mixing, also chelating; option D advises antacids, which similarly bind. These distractors highlight common administration errors. A pearl is to take doxycycline with water, upright, to avoid esophagitis. Framework: Educate on food/drug interactions for antibiotics to optimize bioavailability.

Question 18

1. Valacyclovir 500 mg PO twice daily for 3 days
2. Valacyclovir 1 g PO three times daily for 7 days (correct answer)
3. Valacyclovir 1 g PO once daily for 5 days
4. Valacyclovir 2 g PO twice daily for 1 day

Explanation: This question tests the appropriate dosing regimen for valacyclovir in herpes zoster (shingles) treatment. Key patient-specific factors include age 34 years, normal renal function (eGFR 105 mL/min/1.73 m²), and rash onset within 36 hours, allowing optimal antiviral efficacy. The best choice is valacyclovir 1 g PO three times daily for 7 days, as IDSA and CDC guidelines recommend this for immunocompetent adults to reduce pain duration and postherpetic neuralgia risk when started within 72 hours. Option A is the genital herpes regimen, too low for zoster; option C uses suppression dosing; option D is for cold sores, insufficient duration. These distractors confuse indications across herpesvirus infections. A clinical pearl is to initiate antivirals promptly in zoster for best outcomes, adjusting for renal impairment if CrCl <50 mL/min. For similar decisions, differentiate dosing by virus type and patient immunity status per guidelines.

Question 19

1. Inhale the contents of 1 capsule (18 mcg) once daily using the HandiHaler device (correct answer)
2. Inhale 2 capsules (36 mcg) twice daily
3. Inhale 1 capsule every 4 hours as needed for shortness of breath
4. Swallow 1 capsule (18 mcg) PO once daily

Explanation: This question tests the appropriate dosing regimen for tiotropium HandiHaler in COPD maintenance. Key patient-specific factors include COPD diagnosis, concomitant inhalers, and normal labs allowing standard use. The best choice is to inhale 1 capsule (18 mcg) once daily via HandiHaler, as GOLD guidelines recommend this LAMA dose for bronchodilation. Option B doubles dose/frequency; option C is PRN; option D suggests swallowing, incorrect. These distractors misapply administration. A pearl is to pierce capsules only in device. Framework: Optimize inhaler technique for COPD controllers.

Question 20

1. Increase to tamsulosin 0.8 mg PO once daily if inadequate response after 2–4 weeks (correct answer)
2. Increase to tamsulosin 1.6 mg PO once daily immediately
3. Change to tamsulosin 0.4 mg PO twice daily
4. Add a second alpha-1 blocker (e.g., doxazosin) without changing tamsulosin

Explanation: This question assesses the appropriate dosing regimen adjustment for tamsulosin in managing benign prostatic hyperplasia (BPH) symptoms. Key patient-specific factors include the patient's age, persistent nocturia and weak stream despite initial therapy, normal renal function (SCr 1.0 mg/dL), and stable blood pressure, indicating tolerance to alpha-blocker escalation without significant orthostatic risk. Increasing to tamsulosin 0.8 mg PO once daily if inadequate response after 2–4 weeks is the best choice, aligning with FDA-approved labeling and AUA guidelines for BPH, which recommend titrating from 0.4 mg to a maximum of 0.8 mg daily with a monitoring period to assess efficacy and side effects. Immediately increasing to 1.6 mg (choice B) exceeds the maximum recommended dose and risks adverse effects like hypotension; changing to 0.4 mg twice daily (choice C) is inappropriate as tamsulosin is formulated for once-daily extended-release administration. Adding a second alpha-1 blocker like doxazosin (choice D) is suboptimal without first maximizing tamsulosin monotherapy and could increase side effect burden unnecessarily. A transferable clinical pearl is that alpha-blockers for BPH should be titrated gradually to balance symptom relief with minimizing dizziness or hypotension, especially in older adults. In practice, employ a stepwise framework: evaluate response after 2-4 weeks at starting dose, titrate to max if needed, and consider combination therapy only if monotherapy fails.