Pharmacology NCLEX Questions: 10 Practice Items with Rationales

Pharmacology items are rarely about remembering a drug. They are about deciding what to do with a number in front of you: hold or give, escalate or monitor, reverse or wait.

This is a practice set. Ten annotated items across the four highest-yield drug classes, plus an unfolding NGN case, with a rationale on every option rather than only the key. For the test-plan breakdown and the high-yield drug reference, see our NCLEX pharmacology guide; this article assumes that and gets to the questions.

Exam preparation, not a clinical protocol. Doses and thresholds vary by institution. Follow your facility's protocols and current prescriber orders in practice.

Five patterns pharmacology items follow

Nearly every pharmacology item is one of five shapes. Naming the shape before reading the options is the fastest way to stop being pulled toward answers that are true but not asked for.

Anticoagulants: heparin, warfarin and NOACs

The tested distinction is which agent reverses which drug. Protamine sulfate reverses heparin. Vitamin K reverses warfarin. Swapping them is the most common error in this class, and both appear as distractors precisely because of that.

Heparin is monitored by aPTT, warfarin by INR. Both are ISMP high-alert medications, meaning an error carries disproportionate risk of harm.

Question 1

A client on a continuous IV heparin infusion for pulmonary embolism has an aPTT of 185 seconds. The provider has not yet been reached. Which action should the nurse take first?

A. Continue the infusion at the current rate and reassess in one hour B. Stop the heparin infusion and notify the provider immediately C. Reduce the infusion rate by half and recheck the aPTT in 30 minutes D. Administer protamine sulfate 50 mg IV per standing protocol

Correct answer: B.

• A is incorrect. The aPTT is far above therapeutic range and the client is actively bleeding-risk. Continuing at rate compounds the problem for another hour.

• B is correct. Stop the infusion first to prevent further anticoagulation, then escalate. This is the hold-or-give pattern: a value outside the safe parameter means hold and notify.

• C is incorrect. Halving the rate still delivers heparin to a client who is already over-anticoagulated. Partial action on a dangerous value is not a safe compromise.

• D is incorrect, and it is the trap. Protamine is the correct antidote, but administering it is a provider decision, and the option's "standing protocol" framing invites you to skip escalation. Recognizing the right drug does not authorize giving it.

Question 2

A client taking warfarin has an INR of 5.8 and reports dark, tarry stools. What is the most appropriate intervention?

A. Continue warfarin and reassess in 24 hours B. Administer vitamin K as prescribed C. Give protamine sulfate D. Administer naloxone

Correct answer: B.

• A is incorrect. Melena with a markedly elevated INR indicates active gastrointestinal bleeding. Twenty-four hours of continued warfarin is dangerous.

• B is correct. Vitamin K reverses warfarin by restoring the clotting factors it suppresses.

• C is incorrect. Protamine reverses heparin, not warfarin. This is the swap the class is built to test.

• D is incorrect. Naloxone reverses opioids and has no relationship to anticoagulation.

Insulin: onset, peak and hypoglycemia

Insulin items turn on timing. Knowing when a given insulin peaks tells you when hypoglycemia is most likely, which is what the questions actually ask. You will rarely be asked to name an insulin; you will constantly be asked what to do at a given hour after a given dose, or which insulin explains a glucose reading in front of you. The four categories below differ in onset and, more importantly, in whether they have a pronounced peak at all. That single property is what drives the risk window, and it is the reason NPH generates more exam items than the other three combined.

Two administration rules recur: regular insulin is clear and NPH is cloudy, and when mixing them in one syringe you draw clear before cloudy.

For hypoglycemia, the intervention depends on level of consciousness. A conscious client able to swallow gets 15 grams of fast-acting carbohydrate. An unconscious client gets glucagon or IV dextrose. Endocrine emergencies more broadly are covered in our endocrine NCLEX questions set.

Question 3

A client with type 1 diabetes received NPH insulin at 07:00. The client is at highest risk for hypoglycemia at which time?

A. 08:00–09:00 · B. 10:00–11:00 · C. 11:00–19:00 · D. After midnight

Correct answer: C.

• A is incorrect. One to two hours post-dose is within NPH's onset window, not its peak.

• B is incorrect. Closer, but still ahead of the peak.

• C is correct. NPH peaks roughly 4 to 12 hours after administration. From 07:00 that window is 11:00 to 19:00.

• D is incorrect. More than 17 hours out, NPH activity is declining rather than peaking.

Question 4

A client with type 1 diabetes reports feeling shaky, sweaty and dizzy. Blood glucose is 54 mg/dL. The client is alert and able to swallow. What is the nurse's first action?

A. Administer IV dextrose (D50W) B. Give 15 g of fast-acting carbohydrate C. Administer glucagon IM D. Recheck blood glucose in 30 minutes

Correct answer: B.

• A is incorrect. IV dextrose is reserved for clients who cannot take oral carbohydrate. It is more invasive than this situation requires.

• B is correct. Alert and able to swallow means the oral route is available, and 15 grams of fast-acting carbohydrate is the standard first step.

• C is incorrect. Glucagon is for the unconscious or unable-to-swallow client, for the same reason as A.

• D is incorrect. Waiting 30 minutes treats a confirmed hypoglycemic episode with observation instead of glucose.

Antipsychotics and psychiatric medications

The critical distinction in this class is extrapyramidal symptoms versus neuroleptic malignant syndrome. EPS are manageable adverse effects that are treated and monitored; NMS is a medical emergency that stops the drug immediately. Items here almost always present a client on an antipsychotic with a cluster of findings and ask which one requires immediate attention, and the answer turns on telling those two categories apart. Lithium follows the same logic with a different vocabulary, staging toxicity by severity rather than by symptom type. Both are recognition problems before they are intervention problems.

EPS come in four forms: acute dystonia (sudden muscle spasms, treated with diphenhydramine or benztropine), akathisia (restlessness, inability to sit still), pseudoparkinsonism (tremor, shuffling gait, mask-like facies), and tardive dyskinesia (involuntary movements, potentially permanent).

NMS presents with high fever, severe muscle rigidity, confusion and autonomic instability. The antipsychotic is stopped immediately and urgent treatment sought.

Lithium items test toxicity staging: mild produces fine tremor, nausea and diarrhea; moderate adds slurred speech, confusion and poor coordination; severe brings seizures and coma. Separately, SSRIs can cause serotonin syndrome, particularly combined with MAOIs, triptans or tramadol, presenting with fever, agitation, diarrhea and muscle twitching.

Question 5

A client with schizophrenia is prescribed haloperidol. Which finding requires immediate attention?

A. Mild dry mouth · B. Blurred vision · C. Muscle rigidity and high fever · D. Increased appetite

Correct answer: C.

• A and B are incorrect. Both are anticholinergic effects, expected and not urgent.

• C is correct. Rigidity with hyperthermia is neuroleptic malignant syndrome, which is life-threatening and requires stopping the drug immediately.

• D is incorrect. Weight gain is a known long-term effect of antipsychotics and a management issue rather than an emergency.

Question 6

A client taking lithium reports diarrhea, vomiting and tremors. What is the priority action?

A. Encourage increased fluid intake B. Hold the medication and notify the provider C. Give the next scheduled dose with food D. Reassure the client these are expected effects

Correct answer: B.

• A is incorrect. Hydration matters in lithium management, but it does not address a client currently showing toxicity.

• B is correct. This triad indicates lithium toxicity. Hold and escalate.

• C is incorrect. Giving another dose during toxicity worsens it, and food changes nothing about that.

• D is incorrect. These are toxicity signs, not expected effects, and reassurance delays treatment.

Opioids and pain management

Opioids are ISMP high-alert medications, and respiratory status is the priority assessment before and after administration. Pain relief matters; respiratory rate, level of consciousness and oxygenation decide whether the drug is given at all.

Naloxone is the reversal agent. On PCA, only the patient presses the button, and the lockout interval exists to prevent overdose.

Question 7

A patient receives naloxone for opioid overdose. Which action is most important afterward?

A. Discontinue monitoring because the overdose has been reversed B. Monitor for recurrent respiratory depression C. Encourage immediate ambulation D. Administer a second dose of morphine for pain

Correct answer: B.

• A is incorrect, and dangerously so, for the reason B is correct.

• B is correct. Naloxone has a shorter duration of action than many opioids, so respiratory depression can return once it wears off. This single pharmacokinetic fact is what the item exists to test.

• C is incorrect. Ambulation is unsafe in a patient recovering from opioid-induced respiratory depression.

• D is incorrect. Re-dosing the opioid reverses the reversal.

Question 8

A nurse is preparing morphine for a postoperative patient. Which finding requires holding the drug and notifying the provider?

A. Pain rating of 8/10 · B. Respiratory rate of 10/min · C. BP 138/84 · D. Heart rate 92

Correct answer: B.

• A is incorrect. Severe pain is the indication for morphine, not a contraindication.

• B is correct. A rate below 12 suggests respiratory depression, the adverse effect that decides whether an opioid is safe to give.

• C and D are incorrect. Both are within normal limits and neither relates to opioid safety.

An unfolding NGN case: insulin and hypoglycemia

NGN cases present one situation across several linked items, each testing a different step of clinical judgment. Per NCSBN, they have appeared on every NCLEX-RN since April 2023, and our NGN item type guide covers each format and how it is scored.

Scenario. A 45-year-old with type 1 diabetes receives NPH insulin at 07:00. At 11:30 the patient is diaphoretic, shaky and confused. Blood glucose is 48 mg/dL.

Item A: recognize cues (select all that apply)

Which findings indicate hypoglycemia?

A. Diaphoresis · B. Shakiness · C. Confusion · D. Blood glucose 48 mg/dL · E. Fruity breath odor

Correct: A, B, C, D.

• A correct. Sweating is a classic adrenergic sign of hypoglycemia.

• B correct. Tremor is adrenergic as well.

• C correct. Confusion is neuroglycopenic, reflecting reduced glucose to the brain.

• D correct. 48 mg/dL confirms it.

• E incorrect. Fruity breath indicates ketoacidosis, the opposite metabolic problem, and it is the discriminating distractor here.

Note the timing: 11:30 is exactly inside the 4-to-12-hour NPH peak window from a 07:00 dose. The case is built on Question 3's principle.

The bottom line

Pharmacology items reward pattern recognition over memorization. Name the pattern first, and most items resolve quickly: hold-or-give questions want you to hold and escalate, antidote questions want the agent matched to the drug rather than the symptom, and safe-administration questions want assessment before action.

Two specifics carry more weight than anything else in this set. Protamine reverses heparin and vitamin K reverses warfarin, and they appear as each other's distractors constantly. And naloxone wears off before the opioid does, which is why monitoring continues after reversal.

Notice how many of the wrong answers above are reasonable actions in the wrong order or for the wrong drug. That is what these items measure, and it only improves with practice that explains why each option fails. Our NCLEX-RN question bank works that way, and how to answer NCLEX questions covers the item types these appear in.