NCLEX pharmacology practice questions, with rationales

Pharmacological and Parenteral Therapies is 13-19% of the NCLEX-RN, the second-largest subcategory: expected and adverse effects, contraindications, antidotes, therapeutic levels, safe administration, dosage calculation, blood products, parenteral nutrition and IV therapy. The free drill below is 12 original questions, mixing medication knowledge and calculations, with every rationale explained.

13-19%
of the NCLEX-RN: 14
of our 85 mock questions: 4
calculations in each mock: 12
free drill questions

Last checked 13 November 2026 · Range from the 2026 NCLEX-RN Test Plan (NCSBN); drug facts from FDA labeling and standard references

Free drill: 12 original NCLEX-RN-style questions each, at 2 minutes a question, then every rationale shown. No sign-up.

12
questions
24 min
time limit
Free
every answer explained

By the LifeScore Editorial Team · Updated 13 November 2026 · How we check facts · How this is scored

What pharmacology is on the NCLEX-RN?

The NCLEX does not ask you to recite doses. It asks what to check before giving a drug, what adverse effect to watch for, what to teach, which result means hold the dose, and how to give it safely.

Pharmacology topics and what the questions ask
Topic	What the questions ask
Adverse effects and interactions	Which finding to report: angioedema on an ACE inhibitor, serotonin syndrome, a rash on vancomycin
Monitoring and levels	Which value to check: INR on warfarin, potassium on digoxin and diuretics, lithium and phenytoin levels
Antidotes	Protamine, vitamin K, naloxone, flumazenil, acetylcysteine, calcium gluconate
Safe administration	Insulin mixing and timing, enoxaparin technique, IV potassium, crushing and timing
Blood and blood products	Compatibility, the first 15 minutes, what to do in a reaction
Parenteral and IV therapy	Parenteral nutrition, central lines, infiltration and phlebitis, air embolism
Dosage calculation	Tablets, liquids, IV rates, drip rates, weight-based doses, heparin and titrated drips

What is the fastest way to learn NCLEX pharmacology?

By class: learn the suffix, what the class does, its most dangerous adverse effect, what you monitor, and the antidote. One class card covers dozens of drugs.

High-yield drug classes (suffix, the danger, what to check)
Class (suffix)	Most important danger	Check or teach
ACE inhibitors (-pril)	Angioedema; hyperkalemia	Stop and protect the airway for facial swelling; a dry cough is common
Beta blockers (-olol)	Bradycardia, hypotension; masked hypoglycemia	Apical pulse and blood pressure before giving
Loop diuretics (furosemide)	Hypokalemia, dehydration, ototoxicity	Potassium, weight, I&O; give IV slowly
Potassium-sparing diuretics (spironolactone)	Hyperkalemia	No potassium salt substitutes
Anticoagulants (heparin, warfarin, -xaban)	Bleeding; HIT on heparin	aPTT, INR, platelets; consistent vitamin K on warfarin
Statins (-statin)	Muscle injury (rhabdomyolysis), liver injury	Report unexplained muscle pain
SSRIs and MAOIs	Serotonin syndrome; hypertensive crisis with tyramine (MAOIs)	No other serotonergic drugs; avoid aged cheese and cured meats on MAOIs
Aminoglycosides (-micin, -mycin)	Nephrotoxicity, ototoxicity	Creatinine, hearing, peak and trough

Therapeutic levels the NCLEX expects you to know (typical ranges)
Drug	Typical range	Why it matters
INR on warfarin	Usually 2 to 3 (atrial fibrillation, DVT)	High: bleeding risk; vitamin K reverses warfarin
Lithium (maintenance)	About 0.6 to 1.2 mEq/L	Above about 1.5: toxicity; dehydration and low sodium raise levels
Digoxin	About 0.5 to 2.0 ng/mL (0.5 to 0.9 is often the target in heart failure)	Hold for an adult apical pulse under 60; low potassium raises toxicity

NCLEX-RN-style question 1 · Antidotes
A client receiving warfarin has an INR of 7.8 and is bleeding from the gums. Which medication does the RN expect to be ordered?
1. AProtamine sulfate
2. BVitamin K (phytonadione)
3. CNaloxone
4. DAcetylcysteine
Worked answer
B: Vitamin K (phytonadione). Vitamin K reverses warfarin; with serious bleeding, prothrombin complex concentrate may be given too. Protamine reverses heparin.
1. Which drug? Warfarin.
2. Its reversal agent: vitamin K.
3. Protamine is for heparin, naloxone for opioids, acetylcysteine for acetaminophen.
The trap: Mixing up the two anticoagulant antidotes. Pair them once and keep them: heparin-protamine, warfarin-vitamin K.
NCLEX-RN-style question 2 · Adverse effects
A client taking an ACE inhibitor and a potassium supplement has a serum potassium of 6.2 mEq/L. Which ECG change is the RN most likely to see?
1. AU waves
2. BTall, peaked T waves
3. CA prolonged QT interval with flattened T waves
4. DST depression only
Show the worked answer
B: Tall, peaked T waves. ACE inhibitors retain potassium, and with a supplement the level can climb. Hyperkalemia peaks the T waves first; U waves and flat T waves belong to hypokalemia.
1. ACE inhibitor plus potassium supplement: risk of hyperkalemia.
2. 6.2 mEq/L is above the typical 3.5 to 5.0 range.
3. High potassium: tall, peaked T waves, then a widening QRS.
The trap: Learning ECG signs as a list. Learn them as opposites: low potassium flattens and adds U waves, high potassium peaks.

Four more pharmacology drills

The Pass Pack has four 12-question pharmacology drills with new calculations each time, plus two more full mocks.

The NCLEX-RN Pass Pack gives you 3 full mocks on the real clock, 32 drills of 12 questions for the sections that cost you points, and a predictor that turns your mocks into the odds of reaching your target. One payment, no subscription, and your free score stays free.

Prep courses for these tests usually cost $19 to $129. The NCLEX-RN Pass Pack is US$39 (£29), once.

See the NCLEX-RN Pass Pack How our questions are built and checked

3
timed mocks: 32
topic drills: 1
score predictor

How are NCLEX dosage calculation questions set up?

As a short order and a label, with an on-screen calculator on the real exam. Every one comes back to a few formulas: desired over have, volume over time, volume times drop factor over minutes, and weight in kilograms times the dose per kilogram.

The formulas behind almost every calculation
Question	Formula	Example
Tablets or mL	Ordered ÷ on hand × quantity	50 mg ordered, 25-mg tablets: 2 tablets
Pump rate (mL/h)	Volume ÷ hours	1,000 mL over 8 h: 125 mL/h
Gravity drip (gtt/min)	Volume × drop factor ÷ minutes	1,000 mL over 8 h at 15 gtt/mL: 31 gtt/min
Weight-based dose	kg (lb ÷ 2.2) × mg/kg	44 lb child, 10 mg/kg: 20 kg × 10 = 200 mg
Heparin rate	Units/h ÷ units/mL	1,000 units/h, 25,000 units in 250 mL (100 units/mL): 10 mL/h
Titrated drip	mcg/kg/min × kg × 60 ÷ mcg/mL	5 mcg/kg/min, 80 kg, 1,600 mcg/mL: 15 mL/h

NCLEX-RN-style question 1 · Dosage calculation
The order is 1,000 mL of 0.9% sodium chloride over 8 hours by gravity. The tubing delivers 15 gtt/mL. How many drops per minute should the nurse set? Round to the nearest whole drop.
1. A21 gtt/min
2. B31 gtt/min
3. C125 gtt/min
4. D42 gtt/min
Worked answer
B: 31 gtt/min. 1,000 mL × 15 gtt/mL ÷ 480 minutes = 31.25, which rounds to 31 gtt/min.
1. Change hours to minutes: 8 × 60 = 480 min.
2. Multiply volume by drop factor: 1,000 × 15 = 15,000 gtt.
3. Divide: 15,000 ÷ 480 = 31.25, so 31 gtt/min.
The trap: 125 is the pump rate in mL/h. On a gravity set you need drops per minute, so the drop factor and the 60 both come in.
NCLEX-RN-style question 2 · Dosage calculation
A child who weighs 33 lb is prescribed amoxicillin 25 mg/kg/day by mouth in two divided doses. How many milligrams are in each dose? (1 kg = 2.2 lb.)
1. A375 mg
2. B187.5 mg
3. C412.5 mg
4. D825 mg
Worked answer
B: 187.5 mg. 33 lb ÷ 2.2 = 15 kg; 15 × 25 = 375 mg a day; divided into two doses, 187.5 mg each.
1. Convert: 33 ÷ 2.2 = 15 kg.
2. Daily dose: 15 kg × 25 mg/kg/day = 375 mg/day.
3. Per dose: 375 ÷ 2 = 187.5 mg.
The trap: 375 mg is the whole day's amount. "mg/kg/day in divided doses" always means one more division.

Round only at the end, and follow the rounding the question asks for. On the real exam a calculation may be fill-in-the-blank; on ours it is four options, and the wrong options are the slips students make, such as forgetting the 60 or dividing a daily dose only once.

What does the NCLEX ask about blood transfusions and IV therapy?

Mostly safety: two-person verification, normal saline only, staying with the client for the first 15 minutes, and stopping the transfusion first in a reaction. For IV therapy: infiltration versus phlebitis, potassium never as an IV push, and what to hang if parenteral nutrition runs out.

Suspected transfusion reaction (fever, chills, back pain, hives, dyspnea): stop the transfusion first.
Keep the vein open with 0.9% sodium chloride through new tubing.
Stay with the client, check vital signs and notify the provider and the blood bank.
Send the bag and tubing to the blood bank, and collect the samples the protocol asks for.

For parenteral nutrition, a sudden stop can cause rebound hypoglycemia, so most protocols hang 10% dextrose if the next bag is late. For a suspected air embolism from a central line, the classic answer is to clamp the line and place the client on the left side with the head down, then call for help.

Practice these in the free drill above, and in mixed sets on the NCLEX-RN practice test. Lab values that go with these drugs are on NCLEX physiological integrity questions.

What are the most common NCLEX pharmacology mistakes?

Choosing an action before checking the client, mixing up look-alike antidotes, treating a common side effect as an emergency (or the reverse), and forgetting that a teaching question wants the wrong statement.

Hold, then notify: when a finding means the drug may be harmful (a pulse under 60 on digoxin, a lithium level over 1.5), the first action is usually to hold the dose.
A dry cough on an ACE inhibitor is common; swelling of the lips or tongue is an emergency.
Never double a missed dose, and never stop steroids, beta blockers or anticonvulsants abruptly.
Clear before cloudy for insulin; only regular insulin goes IV.
Heparin is reversed with protamine, warfarin with vitamin K.

The plan for fitting pharmacology into your study weeks is in how to pass the NCLEX.

Frequently asked questions

How much of the NCLEX is pharmacology?

Pharmacological and Parenteral Therapies is 13-19% of the NCLEX-RN, and medications appear in other categories too.

Is there a calculator on the NCLEX?

Yes, an on-screen calculator is available during the exam.

Do I need to memorize drug doses for the NCLEX?

Rarely. Focus on classes, adverse effects, monitoring, antidotes and safe administration.

Are these real NCLEX questions?

No. They are original NCLEX-RN-style questions written for LifeScore. LifeScore is not affiliated with NCSBN.

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