Sample questions from our NAPLEX Q-Bank

The sample questions below were taken directly from our NAPLEX Q-Bank.  They represent over a 2,200 other practice test questions you will encounter with the use of our NAPLEX Q-Bank.  We believe our NAPLEX practice test questions will prepare you to pass the NAPLEX exam the first time.  Each question comes with a concise rationale supporting the right answer or concept being tested.   

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Sample NAPLEX Question 1

Which of the following characterize a medication with a desirable and safe therapeutic index (TI) that is less likely to cause toxicity if there is an accidental overdose?  (Select all that apply)

  1. A medication with a long half-life in the body
  2. A medication with a large LD50 in comparison to the ED50
  3. A medication that exhibits zero-order elimination kinetics
  4. A medication with a TI that is large

Answer = b, d


  • Only the second and last answer choices describe a medication with a safe or desirable therapeutic index (TI). 
  • By definition, the TI is the LD50/ED50 for a medication.  The LD50 is the dose or drug concentration that is lethal in 50% of patients and the ED50 is the dose or drug concentration that exerts the desired pharmacologic effect in a patient. Therefore, the larger the LD50 compared to the ED50 the safer the medication.
  • The larger the TI the lower risk in lethal toxicity if there is an accidental or intentional overdose.
  • Medications with small TIs are more likely to cause toxicity if used outside the normal dosing and are less forgiving if a mistake is made. 
  • Medications with long half-lives can create a challenge during an accidental overdose due to the maintained pharmacologic effects of the drug over time. However, long half-lives do not necessary mean the medications are unsafe or have a small TI, because a safer and desirable TI involves the margin of difference between the LD50 and ED50.  This pertains to the first answer choice.
  • Medications that exhibit zero-order elimination kinetics generally have a less than desirable safety profile, which is in part why most FDA-approved medications exhibit first-order elimination kinetics. This pertains to the third answer choice.

High-Yield Core Concept:

  • The therapeutic index (TI) is the LD50/ED50 for a medication, and the larger the LD50 compared to the ED50 the safer the medication. 
  • Medications with a TI > 10 are generally considered to have a safer profile.

High-Yield Fast Fact(s):

  • Lithium and digoxin are classically  known to have a very small TI and thus are categorized as drugs having a "narrow therapeutic index".


  • Br J Clin Pharmacol 2000;49(4):303-312
  • Am J Cardiol 2012;109:1818-1821. 

Sample NAPLEX Question 2

A 54 year old male with past medical history of hypertension, gout, and arthritis who presents to the emergency department with reports of photophobia and extreme headaches. On exam he is neck stiffness and There is significant concern for bacterial meningitis. He is not allergic to any drugs. Which of the following is the best recommendation?

  1. Ampicillin + cefotaxime
  2. Ampicillin + vancomycin
  3. Cefotaxime + vancomycin
  4. Ampicillin + cefotaxime + vancomycin

Answer = D


  • The IDSA guideline for bacterial meningitis states that ampicillin plus a third-generation cephalosporin plus vancomycin is the empiric regimen of choice for bacterial meningitis in a patient who is > 50 years old.
  • Ampicillin is needed as part of the empiric regimen due to Listeria monocytogenes being a common pathogen for patients > 50 years of age.

High-Yield Core Concept:

  • To identify the optimal empiric treatment for a patient with suspected bacterial meningitis who is > 50 years old.

High-Yield Fast Fact(s):

  • Ceftriaxone and cefotaxime are the only third-generation cephalosporins recommended as empiric therapy since they are the most likely to have clinically relevant activity against multidrug resistant S. pneumoniae.
  • Ceftazidime has no clinically relevant activity against gram-positive pathogens.


  • Clinical Infectious Diseases 2004; 39:1267-84.

Sample NAPLEX Question 3

A 220-pound patient has been placed on a standard heparin drip of 15 units/kg/h intravenously. Heparin comes premixed 25,000 units in 500 mL. How many milliliters per hour will this patient receive?

  1. 20 mL/h
  2. 30 mL/h
  3. 40 mL/h
  4. 50 mL/h

Answer = b


  • Heparin, a parenteral administered anticoagulant, is prescribed to prevent or treat thromboembolic events.
    • First, you should convert his weight from pounds (lb) to kilograms (kg) so 220 lb divided by 2.2 is 100 kg.
    • Then, multiply 100 kg by 15 units/kg/hr which is 1500 units/hr.
    • Next, you would calculate how many units per mL in the premixed heparin solution so 25,000 divided by 500 is 50 units / mL.
    • Finally, 1500 units divided by 50 units is 30 mL/h.

High-Yield Fast Facts:

  • Heparin is also commonly referred to as "unfractionated heparin" and it combines with antithrombin (AT) to most commonly inhibit factors X & II at a 1:1 ratio.  When treating active clots the dose is higher and commonly needs to be administered by an IV infusion.

Sample NAPLEX Question 4

While taking the medication history of a 52 year old female, she mentions she takes an herb for her hot flashes. Which of the following herbal medicinal might she be taking for menopausal symptoms?

  1. Black cohosh
  2. Bromelain
  3. Lavender
  4. Tumeric

Answer = a


  • Actaea racemose (black cohosh) is used for hot flashes, other menopausal symptoms, menstrual cramps and premenstrual syndrome, and to induce labor despite limited data on its efficacy.

High-Yield Core Concept:

  • Clinicians should be familiar with common uses of herbal medicinals despite lack of rigorous scientific data.

High-Yield Fast Facts:

  • Liver damage has been reported with use of black cohosh so patients with liver disorders should consult with their healthcare provider before starting black cohosh as well as if a patient experience signs and symptoms of liver damage should stop taking black cohosh and consult with their healthcare provider.
  • There are no significant drug interactions with black cohosh.
  • Bromelain is used for nasal swelling and inflammation, osteoarthritis, cancer, poor digestion, and muscle soreness. There is limited data in osteoarthritis, cancer, digestion, and muscle soreness to prove bromelain's efficacy.
  • Lavandula angustifolia (lavender) is used for anxiety, depression, intestinal problems, hair loss, and pain despite no clinical data.
  • Curcuma aromatic (turmeric) is used for inflammation and arthritis, stomach, skin, liver, and gallbladder problems, and cancer despite limited data.


  • Am J Obstet Gynecol. 2008 Nov;199(5):455-66.
  • Planta Med. 2012 Sep;78(13):1490-514.