Adverse Effects and Interactions Practice Questions

77 multiple-choice questions on Adverse effects and interactions for paramedic and EMT students, from Chapter 13 (Principles of Pharmacology). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

77 practice questions

1. An adverse reaction that is dose-related and predictable from a drug's known actions, such as bleeding with warfarin, is classified as:

   1. A. Type A (augmented)
   2. B. Type B (bizarre)
   3. C. An IgE-mediated allergy
   4. D. An idiosyncratic reaction
   Show answer

   Answer: A. Type A (augmented)

   Type A (augmented) reactions exaggerate a drug's normal pharmacology, are dose-related, and make up most adverse reactions. Type B (bizarre) reactions are unpredictable and not dose-related; they include an IgE-mediated allergy and an idiosyncratic reaction.

2. An adverse effect is:

   1. A. A reaction seen only after an overdose
   2. B. Identical to a side effect in every case
   3. C. An unintended, harmful response to a drug
   4. D. A desired therapeutic response to a drug
   Show answer

   Answer: C. An unintended, harmful response to a drug

   Adverse events should be reported through appropriate channels.

3. A true drug allergy involves:

   1. A. An immune-mediated reaction
   2. B. Any unpleasant drug effect
   3. C. Nausea after taking a dose
   4. D. An expected side effect
   Show answer

   Answer: A. An immune-mediated reaction

   Ask what happened when a patient reports an allergy. It may range from rash to anaphylaxis.

4. After topical benzocaine throat spray before a procedure, a patient is cyanotic with an SpO2 near 85% that stays there despite 100% oxygen. You should suspect:

   1. A. Benzocaine-induced bronchospasm
   2. B. Carbon monoxide poisoning
   3. C. Methemoglobinemia
   4. D. Aspiration of the spray
   Show answer

   Answer: C. Methemoglobinemia

   This is methemoglobinemia: benzocaine oxidizes hemoglobin to methemoglobin, which cannot carry oxygen; pulse oximetry tends to read near 85% regardless of oxygen, and blood may look chocolate-brown. Treatment is oxygen and methylene blue. Benzocaine-induced bronchospasm would cause wheezing, carbon monoxide poisoning usually gives a falsely normal SpO2, and aspiration of the spray would not cause this pattern.

5. The FDA warns that gabapentin or pregabalin taken with opioids increases the risk of:

   1. A. Serotonin syndrome with clonus
   2. B. Hypertensive crisis
   3. C. Serious respiratory depression
   4. D. Opioid withdrawal
   Show answer

   Answer: C. Serious respiratory depression

   Gabapentinoids are CNS depressants; combined with opioids or other sedatives they can cause serious respiratory depression, especially in older adults and patients with lung disease (FDA, 2019). They do not cause serotonin syndrome with clonus, hypertensive crisis, or opioid withdrawal.

6. A patient on long-term digoxin is started on amiodarone. The interaction to expect is:

   1. A. Lower digoxin levels and lost effect
   2. B. Higher digoxin levels and toxicity
   3. C. Hypokalemia caused by amiodarone
   4. D. Faster renal clearance of digoxin
   Show answer

   Answer: B. Higher digoxin levels and toxicity

   Amiodarone inhibits P-glycoprotein and reduces digoxin clearance, roughly doubling digoxin levels, so the digoxin dose is usually reduced. It does not cause lower digoxin levels and lost effect, hypokalemia caused by amiodarone is not the interaction, and it slows rather than speeds renal clearance of digoxin.

7. Antagonism between drugs means:

   1. A. One drug triggers an allergy to the other
   2. B. Their combined effect exceeds the sum
   3. C. Their effects add together equally
   4. D. One drug lessens another's effect
   Show answer

   Answer: D. One drug lessens another's effect

   Naloxone reversing opioids is therapeutic antagonism.

8. A patient with angina is told to remove his nitroglycerin patch for 10 to 12 hours each night. The purpose is to:

   1. A. Avoid cyanide accumulation
   2. B. Let the skin site heal
   3. C. Prevent rebound hypertension
   4. D. Prevent nitrate tolerance
   Show answer

   Answer: D. Prevent nitrate tolerance

   Continuous nitrate exposure quickly produces tolerance, so a daily nitrate-free interval keeps the drug effective. Cyanide accumulation is a risk of nitroprusside, not nitroglycerin; rotating sites, not a nightly break, lets the skin site heal; and nitrates lower blood pressure, so the break is not to prevent rebound hypertension.

9. Benzodiazepines are the first-line treatment for alcohol withdrawal mainly because:

   1. A. They speed the liver's metabolism of alcohol
   2. B. They block alcohol at NMDA receptors
   3. C. Both enhance GABA-A, giving cross-tolerance
   4. D. They reverse alcohol-related liver damage
   Show answer

   Answer: C. Both enhance GABA-A, giving cross-tolerance

   Alcohol and benzodiazepines both enhance GABA-A activity and show cross-tolerance, so a benzodiazepine substitutes for alcohol and prevents seizures and delirium tremens. Benzodiazepines do not speed the liver's metabolism of alcohol, do not block alcohol at NMDA receptors, and do not reverse alcohol-related liver damage.

10. Eighteen hours after his last heroin use, a man has yawning, a runny nose, dilated pupils, diarrhea, and gooseflesh, with stable vital signs. This is:

    1. A. Opioid withdrawal
    2. B. Opioid toxicity
    3. C. Anticholinergic toxicity
    4. D. Serotonin syndrome
    Show answer

    Answer: A. Opioid withdrawal

    Withdrawal from physical dependence produces the opposite of opioid effects: yawning, rhinorrhea, dilated pupils, diarrhea, and piloerection; it is miserable but rarely life-threatening. Opioid toxicity causes small pupils and respiratory depression, anticholinergic toxicity causes dry skin and absent bowel sounds, and serotonin syndrome features clonus and hyperthermia.

11. Withdrawal from alcohol or benzodiazepines is more dangerous than opioid withdrawal because it can cause:

    1. A. Pinpoint pupils with apnea and coma
    2. B. Severe hypoglycemic coma
    3. C. Profound bradycardia
    4. D. Seizures and delirium tremens
    Show answer

    Answer: D. Seizures and delirium tremens

    Abrupt loss of chronic GABA enhancement leaves the brain overexcited: tremor, tachycardia, hyperthermia, seizures, and delirium tremens, which can be fatal. Pinpoint pupils with apnea and coma describe opioid toxicity, not withdrawal; severe hypoglycemic coma is not the pattern; and withdrawal causes tachycardia rather than profound bradycardia.

12. A cumulative effect occurs when:

    1. A. A drug is fully eliminated between doses
    2. B. Dosing outpaces elimination of the drug
    3. C. Tolerance develops with repeated doses
    4. D. Two drugs interact to enhance each other
    Show answer

    Answer: B. Dosing outpaces elimination of the drug

    Impaired renal or hepatic function makes it more likely. The drug then accumulates in the body.

13. A teratogenic drug is one that:

    1. A. Commonly causes allergic reactions
    2. B. Has a high potential for addiction
    3. C. May harm the developing fetus
    4. D. Raises maternal blood pressure
    Show answer

    Answer: C. May harm the developing fetus

    Always ask about possible pregnancy before administration. This includes malformation.

14. A rare but serious airway adverse effect of ketamine, more common in young children and with airway stimulation, is:

    1. A. Laryngospasm
    2. B. Chest wall rigidity
    3. C. Angioedema of the tongue
    4. D. Severe bronchospasm
    Show answer

    Answer: A. Laryngospasm

    Laryngospasm occurs in a small share of ketamine sedations, is usually brief, and is treated with jaw thrust and positive-pressure ventilation. Chest wall rigidity is linked to rapid high-dose fentanyl, angioedema of the tongue to ACE inhibitors, and ketamine relaxes bronchial smooth muscle, so severe bronchospasm is not expected.

15. During a rapid vancomycin infusion on an interfacility transfer, the patient develops flushing and itching of the face and neck with normal vital signs and no wheezing. The best first step is to:

    1. A. Give IM epinephrine immediately
    2. B. Keep the rate and give oxygen by mask
    3. C. Continue unchanged, since vitals are normal
    4. D. Stop or slow the infusion
    Show answer

    Answer: D. Stop or slow the infusion

    This is a vancomycin infusion reaction (formerly 'red man syndrome'): a rate-related, non-IgE histamine release. Stop or slow the infusion and consider an antihistamine. With no airway, breathing, or blood pressure involvement it is not anaphylaxis, so IM epinephrine immediately is not needed. Continuing at the same rate, with or without oxygen, keeps the rate-related histamine release going.

16. A patient had a mild rash with penicillin as a child and now needs ceftriaxone. Current evidence puts the cross-reactivity risk at:

    1. A. About 50 percent
    2. B. Higher with later generations
    3. C. Equal to the penicillin risk
    4. D. About 1 to 2 percent
    Show answer

    Answer: D. About 1 to 2 percent

    Cross-reactivity between penicillins and cephalosporins is low, roughly 1 to 2 percent, and lowest with later-generation drugs such as ceftriaxone whose side chains differ; many reported penicillin allergies are not true allergies. About 50 percent is far too high, risk is not higher with later generations, and it is not equal to the penicillin risk.

17. Anaphylaxis is:

    1. A. A toxic reaction caused by drug overdose
    2. B. A mild, localized hives reaction at the IV site
    3. C. A life-threatening systemic allergic reaction
    4. D. A predictable dose-related side effect of most drugs
    Show answer

    Answer: C. A life-threatening systemic allergic reaction

    Anaphylaxis is a severe, life-threatening systemic allergic reaction that requires epinephrine and airway management.

18. Which drug class is a common cause of serious allergic reactions?

    1. A. Loop diuretics such as furosemide
    2. B. Antibiotics such as penicillins
    3. C. Electrolytes such as potassium
    4. D. Antiemetics such as ondansetron
    Show answer

    Answer: B. Antibiotics such as penicillins

    Beta-lactam antibiotics are frequently implicated. Allergic reactions to furosemide and ondansetron occur but are uncommon, whereas penicillins are among the most frequent causes.

19. Seven days after starting heparin, a hospitalized patient's platelet count falls by half and a new leg DVT forms. You should suspect:

    1. A. Warfarin-induced skin necrosis
    2. B. Heparin overdose with active bleeding
    3. C. Vitamin K deficiency
    4. D. Heparin-induced thrombocytopenia
    Show answer

    Answer: D. Heparin-induced thrombocytopenia

    Heparin-induced thrombocytopenia is an immune reaction, usually 5 to 10 days after starting heparin, in which antibodies activate platelets so platelets fall while clots form; heparin is stopped and a nonheparin anticoagulant started. Warfarin-induced skin necrosis affects skin, heparin overdose with active bleeding would not form new clots, and vitamin K deficiency causes bleeding, not thrombosis.

20. Which home medication is a known teratogen that should prompt you to ask about possible pregnancy?

    1. A. Acetaminophen
    2. B. Levothyroxine
    3. C. Valproic acid
    4. D. Insulin glargine
    Show answer

    Answer: C. Valproic acid

    Valproic acid causes neural tube defects and other birth defects, so pregnancy status matters. Acetaminophen is the usual analgesic in pregnancy, levothyroxine replaces a needed hormone, and insulin glargine controls diabetes, which itself protects the fetus.

21. Drug-drug interactions can occur through:

    1. A. Pharmacokinetic or pharmacodynamic mechanisms
    2. B. Chemical incompatibility in the IV line only
    3. C. Receptor competition between the two drugs only
    4. D. Shared allergic cross-sensitivity only
    Show answer

    Answer: A. Pharmacokinetic or pharmacodynamic mechanisms

    Interactions can be pharmacokinetic (altered absorption, metabolism, or excretion) or pharmacodynamic (additive or opposing effects).

22. Combining opioids and benzodiazepines increases the risk of:

    1. A. A lowered seizure threshold
    2. B. Rebound tachycardia and agitation
    3. C. Hypertensive crisis and stroke
    4. D. Profound respiratory depression
    Show answer

    Answer: D. Profound respiratory depression

    Both are CNS depressants with synergistic respiratory effects; the combination can cause profound respiratory depression and death.

23. A patient has an irregular, very fast, wide-complex tachycardia from atrial fibrillation with WPW. AV nodal blockers such as adenosine or diltiazem are dangerous because they:

    1. A. Slow the accessory pathway more than the node
    2. B. Favor conduction down the accessory pathway
    3. C. Are metabolized slowly in WPW
    4. D. Cause severe hypertension
    Show answer

    Answer: B. Favor conduction down the accessory pathway

    With the AV node blocked, more atrial impulses race down the accessory pathway, which has no rate-limiting delay, and the rhythm can degenerate into ventricular fibrillation; use procainamide or synchronized cardioversion. These drugs do not slow the accessory pathway more than the node, they are not metabolized slowly in WPW, and they do not cause severe hypertension.

24. Monoamine oxidase inhibitors (MAOIs) interact dangerously with:

    1. A. Aspirin and other NSAIDs like ibuprofen
    2. B. Sympathomimetics and meperidine
    3. C. Calcium channel blockers like diltiazem
    4. D. Benzodiazepines such as midazolam
    Show answer

    Answer: B. Sympathomimetics and meperidine

    MAOIs block catecholamine breakdown. Sympathomimetics and certain opioids (e.g., meperidine) can cause hypertensive crisis or serotonin syndrome.

25. Grapefruit juice affects drug metabolism by:

    1. A. Inducing CYP3A4, lowering some drug levels
    2. B. Inhibiting CYP3A4, raising some drug levels
    3. C. Speeding renal excretion of many drugs
    4. D. Binding drugs in the gut and blocking absorption
    Show answer

    Answer: B. Inhibiting CYP3A4, raising some drug levels

    CYP3A4 inhibition increases levels of certain statins, calcium channel blockers, and others.

26. A drug incompatibility occurs when:

    1. A. Two drugs mixed in a line react chemically
    2. B. Two drugs given in sequence have opposing effects
    3. C. A patient's body cannot metabolize a drug
    4. D. A drug is given to the wrong patient
    Show answer

    Answer: A. Two drugs mixed in a line react chemically

    Incompatibility occurs when drugs mixed in the same syringe or IV line react chemically, for example forming a precipitate. Example: sodium bicarbonate and calcium chloride. Opposing effects in the body are an antagonistic interaction, not an incompatibility.

27. Serotonin syndrome can result from combining:

    1. A. Insulin with oral sulfonylureas
    2. B. SSRIs with other serotonergic drugs
    3. C. Beta blockers with NSAIDs such as ibuprofen
    4. D. Benzodiazepines with opioid analgesics
    Show answer

    Answer: B. SSRIs with other serotonergic drugs

    Serotonergic combinations include SSRIs with tramadol, MAOIs, and in some cases ondansetron. Signs include hyperthermia, clonus, agitation, and autonomic instability.

28. A patient takes both metoprolol and diltiazem. The main interaction risk is:

    1. A. Reflex tachycardia and palpitations
    2. B. Hyperkalemia
    3. C. Additive bradycardia and AV block
    4. D. Hypertensive crisis
    Show answer

    Answer: C. Additive bradycardia and AV block

    Beta blockers and nondihydropyridine calcium channel blockers both slow the SA and AV nodes and weaken contraction, so together they can cause marked bradycardia, AV block, and hypotension; use caution giving IV diltiazem to a patient on a beta blocker. They do not cause reflex tachycardia and palpitations, hyperkalemia, or a hypertensive crisis.

29. Shortly after a rapid IV push of prochlorperazine, a patient becomes intensely restless and cannot sit still. This is:

    1. A. Serotonin syndrome
    2. B. Anticholinergic delirium
    3. C. An allergic reaction
    4. D. Akathisia
    Show answer

    Answer: D. Akathisia

    Akathisia is an extrapyramidal effect of dopamine antagonists such as prochlorperazine, metoclopramide, and droperidol, more likely after a rapid IV push; slower infusion helps, and diphenhydramine treats it. Serotonin syndrome needs serotonergic drugs and shows clonus and hyperthermia, anticholinergic delirium shows hot, dry skin, and an allergic reaction shows hives, wheezing, or hypotension.

30. A patient taking apixaban asks whether he can take ibuprofen for back pain. The concern is:

    1. A. Added bleeding risk from platelet inhibition
    2. B. Ibuprofen reverses apixaban's anticoagulant effect
    3. C. Ibuprofen triggers clot formation
    4. D. Reduced absorption of apixaban
    Show answer

    Answer: A. Added bleeding risk from platelet inhibition

    NSAIDs inhibit platelets and irritate the GI lining, so combining them with an anticoagulant raises the risk of serious bleeding; acetaminophen is usually preferred. Ibuprofen does not reverse apixaban's anticoagulant effect, it does not trigger clot formation, and it does not cause reduced absorption of apixaban.

31. Which drug interaction increases the risk of hyperkalemia?

    1. A. ACE inhibitors with potassium-sparing diuretics
    2. B. Thiazide diuretics with corticosteroids like prednisone
    3. C. Insulin infusion combined with sodium bicarbonate
    4. D. Loop diuretics combined with inhaled beta-2 agonists
    Show answer

    Answer: A. ACE inhibitors with potassium-sparing diuretics

    Both ACE inhibitors and potassium-sparing diuretics raise potassium; combined, they can cause dangerous levels. The other combinations tend to lower potassium.

32. Succinylcholine is dangerous in patients with hyperkalemia or burns/crush injuries because it:

    1. A. Releases more potassium from muscle cells
    2. B. Shifts potassium into cells, causing hypokalemia
    3. C. Causes severe vasodilation and hypotension
    4. D. Triggers histamine-mediated bronchospasm
    Show answer

    Answer: A. Releases more potassium from muscle cells

    Depolarization releases intracellular potassium, which can raise an already high level enough to cause cardiac arrest.

33. A paradoxical reaction is:

    1. A. An effect opposite to the one expected
    2. B. An immune-mediated reaction to the drug
    3. C. A reduced effect after repeated doses
    4. D. An exaggerated form of the expected effect
    Show answer

    Answer: A. An effect opposite to the one expected

    Example: agitation from a sedative. Paradoxical reactions are more common in children and the elderly.

34. Nephrotoxic drugs include:

    1. A. Ondansetron, heparin, and intranasal naloxone
    2. B. NSAIDs, aminoglycosides, and IV contrast
    3. C. Opioids, benzodiazepines, and ketamine
    4. D. Metoprolol, diltiazem, and digoxin
    Show answer

    Answer: B. NSAIDs, aminoglycosides, and IV contrast

    Renal impairment increases risk. NSAIDs, aminoglycosides, and IV contrast can injure the kidney directly. Digoxin is cleared by the kidneys but does not damage them, and the other combinations are not typical nephrotoxins.

35. Hepatotoxicity is a notable concern with overdose of:

    1. A. Aspirin (low-dose)
    2. B. Acetaminophen
    3. C. Ibuprofen (Advil)
    4. D. Naloxone (Narcan)
    Show answer

    Answer: B. Acetaminophen

    Acetaminophen overdose causes delayed liver failure.

36. Salicylate (aspirin) toxicity presents with:

    1. A. Bradycardia, hypotension, and heart block
    2. B. Tinnitus, hyperventilation, and acidosis
    3. C. Dry skin, mydriasis, and urinary retention
    4. D. Pinpoint pupils and slow, shallow respirations
    Show answer

    Answer: B. Tinnitus, hyperventilation, and acidosis

    Aspirin stimulates the respiratory center and causes metabolic acidosis, producing a mixed acid-base disturbance along with tinnitus.

37. An older patient started on amlodipine develops ankle swelling and is then given furosemide, which causes dehydration and a fall. This sequence is called a:

    1. A. Paradoxical reaction
    2. B. Prescribing cascade
    3. C. Idiosyncratic reaction
    4. D. Cumulative effect
    Show answer

    Answer: B. Prescribing cascade

    A prescribing cascade occurs when a drug's side effect (amlodipine edema) is mistaken for a new condition and treated with another drug, which adds new harms. A paradoxical reaction is the opposite of the expected effect, an idiosyncratic reaction is an unusual individual response, and a cumulative effect is buildup when dosing outpaces elimination.

38. A drug's 'black box warning' indicates:

    1. A. A notice that the drug is near expiration
    2. B. A label for mild, common side effects
    3. C. The FDA's most serious warning about a drug
    4. D. A label identifying a DEA controlled substance
    Show answer

    Answer: C. The FDA's most serious warning about a drug

    A boxed warning flags potentially life-threatening risks. Example: droperidol QT prolongation warning.

39. QT prolongation is an adverse effect associated with:

    1. A. Ondansetron, haloperidol, and amiodarone
    2. B. Atropine, glucagon, and dextrose
    3. C. Lidocaine, magnesium sulfate, and calcium
    4. D. Diltiazem, adenosine, and metoprolol
    Show answer

    Answer: A. Ondansetron, haloperidol, and amiodarone

    Ondansetron, haloperidol, amiodarone, and some antibiotics prolong the QT interval, risking torsades de pointes. Atropine, glucagon, dextrose, diltiazem, adenosine, and metoprolol are not known for prolonging the QT interval.

40. When giving naloxone to a patient with suspected opioid dependence, titrating small doses to adequate breathing mainly helps avoid:

    1. A. An allergic reaction to naloxone
    2. B. Precipitated withdrawal with vomiting
    3. C. Naloxone-induced respiratory depression
    4. D. Prolonged sedation after waking
    Show answer

    Answer: B. Precipitated withdrawal with vomiting

    Large boluses abruptly displace opioids and can precipitate severe withdrawal: vomiting with aspiration risk, agitation, and occasionally pulmonary edema. The goal is adequate breathing, not full arousal. An allergic reaction to naloxone is rare, naloxone does not cause respiratory depression, and prolonged sedation after waking comes from the opioid outlasting naloxone, not from the dose size.

41. Which adverse effect is expected with morphine?

    1. A. Tachycardia and marked pupillary dilation
    2. B. Respiratory depression and hypotension
    3. C. Diarrhea and increased intestinal motility
    4. D. Severe hypertension and reflex bradycardia
    Show answer

    Answer: B. Respiratory depression and hypotension

    Expected morphine effects include respiratory depression, hypotension, nausea, and pruritus. Opioid side effects are dose-related and predictable.

42. Dextrose given extravascularly can cause:

    1. A. An IgE-mediated local allergic reaction
    2. B. Tissue necrosis from its hypertonicity
    3. C. Rebound hypoglycemia from slow absorption
    4. D. No harm, since dextrose is a natural sugar
    Show answer

    Answer: B. Tissue necrosis from its hypertonicity

    Confirm IV patency before administering concentrated dextrose.

43. Amiodarone's acute adverse effects include:

    1. A. Hypertension and tachycardia
    2. B. Hyperkalemia and peaked T waves
    3. C. Hypotension and bradycardia
    4. D. Bronchospasm and wheezing
    Show answer

    Answer: C. Hypotension and bradycardia

    Rapid infusion causes vasodilation and negative chronotropy.

44. Which antidepressant, taken in overdose, is especially likely to cause seizures, sometimes hours after ingestion?

    1. A. Sertraline
    2. B. Bupropion
    3. C. Mirtazapine
    4. D. Trazodone
    Show answer

    Answer: B. Bupropion

    Bupropion lowers the seizure threshold, and seizures can be delayed with extended-release tablets. Sertraline (an SSRI), mirtazapine, and trazodone are relatively safe in overdose, mostly causing sedation, although sertraline adds serotonin toxicity risk with other serotonergic drugs.

45. Which best reduces the risk of adverse drug events in EMS?

    1. A. Using one standard adult dose for any patient
    2. B. Checking the label once when drawing up
    3. C. Thorough history, correct dosing, and monitoring
    4. D. Relying on the drug box layout to select medications
    Show answer

    Answer: C. Thorough history, correct dosing, and monitoring

    Prevention relies on a thorough allergy and medication history, correct dosing, and monitoring after administration. A single standard dose ignores weight, age, and organ function, and labels should be checked more than once, including just before giving the drug.

46. A patient on a diuretic receiving nitroglycerin may experience:

    1. A. Tachyarrhythmia from nitrate accumulation
    2. B. Exaggerated hypotension from volume depletion
    3. C. Rebound hypertension from fluid retention
    4. D. Bronchospasm from diuretic-induced hypokalemia
    Show answer

    Answer: B. Exaggerated hypotension from volume depletion

    Preload-reducing drugs in volume-depleted patients cause steep BP drops.

47. Accidental intra-arterial injection or extravasation of IV promethazine can cause:

    1. A. Hyperkalemia from local cell breakdown
    2. B. Severe hypoglycemia from insulin release
    3. C. Severe tissue injury and gangrene
    4. D. Profound bradycardia from vagal stimulation
    Show answer

    Answer: C. Severe tissue injury and gangrene

    Promethazine carries an FDA boxed warning for severe tissue injury; many agencies avoid it IV or dilute it.

48. A patient with tricyclic antidepressant overdose has a widening QRS. The appropriate treatment is:

    1. A. Procainamide infusion
    2. B. Flumazenil
    3. C. Sodium bicarbonate
    4. D. Physostigmine
    Show answer

    Answer: C. Sodium bicarbonate

    Bicarbonate overcomes sodium channel blockade and alkalinizes the blood; procainamide worsens it.

49. A patient taking an SGLT2 inhibitor (e.g., empagliflozin) is vomiting with Kussmaul respirations and a glucose of 190 mg/dL. You should suspect:

    1. A. Euglycemic diabetic ketoacidosis
    2. B. Lactic acidosis from the medication
    3. C. Viral gastroenteritis with dehydration
    4. D. Hyperosmolar hyperglycemic state
    Show answer

    Answer: A. Euglycemic diabetic ketoacidosis

    SGLT2 inhibitors can cause DKA with near-normal glucose levels. Lactic acidosis is associated with metformin, not SGLT2 inhibitors.

50. A patient on glyburide is found hypoglycemic and improves with dextrose. Why should transport be encouraged?

    1. A. Hypoglycemia can recur after the dextrose wears off
    2. B. Glyburide stops working once blood glucose is normal
    3. C. Dextrose can trigger dangerous rebound hyperglycemia later
    4. D. Glyburide toxicity must instead be reversed with glucagon
    Show answer

    Answer: A. Hypoglycemia can recur after the dextrose wears off

    Sulfonylurea hypoglycemia can be prolonged and recur after dextrose wears off. Long-acting insulin release from sulfonylureas often requires observation; octreotide may be used in the hospital.

51. A patient taking naltrexone for alcohol use disorder needs pain control after a fracture. You should anticipate:

    1. A. No interaction with opioids
    2. B. A blunted response to opioid analgesics
    3. C. Opioid withdrawal from ketorolac
    4. D. Exaggerated opioid respiratory depression
    Show answer

    Answer: B. A blunted response to opioid analgesics

    Naltrexone is a long-acting opioid antagonist, so non-opioid options such as ketamine may be needed.

52. An 82-year-old recently started on sertraline and hydrochlorothiazide becomes confused and has a seizure. A drug-related cause to suspect is:

    1. A. Hyponatremia
    2. B. Hyperkalemia
    3. C. Hypoglycemia
    4. D. Hypercalcemia
    Show answer

    Answer: A. Hyponatremia

    SSRIs (through inappropriate ADH secretion) and thiazide diuretics both lower sodium, and older adults are most at risk; severe hyponatremia causes confusion and seizures. Thiazides lower rather than raise potassium, so hyperkalemia is unlikely; neither drug causes hypoglycemia; and the mild hypercalcemia thiazides can cause does not explain an acute seizure.

53. Which finding favors serotonin syndrome over neuroleptic malignant syndrome?

    1. A. Lead-pipe rigidity developing over days
    2. B. Recent start of haloperidol
    3. C. Bradycardia and hypothermia
    4. D. Clonus and hyperreflexia with rapid onset
    Show answer

    Answer: D. Clonus and hyperreflexia with rapid onset

    Serotonin syndrome typically begins within hours and features clonus; NMS has slower onset and rigidity.

54. Which opioid carries a particular risk of serotonin syndrome and seizures when combined with an SSRI?

    1. A. Tramadol
    2. B. Hydromorphone
    3. C. Buprenorphine
    4. D. Morphine
    Show answer

    Answer: A. Tramadol

    Tramadol inhibits serotonin reuptake and lowers the seizure threshold.

55. Lithium toxicity may be precipitated by:

    1. A. Acetaminophen or short-term opioid analgesics
    2. B. Dehydration, NSAIDs, or thiazide diuretics
    3. C. Generous fluid intake and a high-sodium diet
    4. D. Antacids or proton pump inhibitors for reflux
    Show answer

    Answer: B. Dehydration, NSAIDs, or thiazide diuretics

    These factors reduce renal lithium clearance, raising serum levels.

56. Digoxin toxicity is more likely in a patient who also takes a loop diuretic because of:

    1. A. Hypercalcemia from the diuretic
    2. B. Hypokalemia
    3. C. Increased digoxin excretion
    4. D. Hyperkalemia
    Show answer

    Answer: B. Hypokalemia

    Low potassium increases digoxin binding to Na/K-ATPase and the risk of arrhythmias.

57. A patient taking digoxin reports nausea and yellow-green visual halos. This suggests:

    1. A. Expected therapeutic effect
    2. B. Beta-blocker overdose
    3. C. Digoxin toxicity
    4. D. Hypoglycemia
    Show answer

    Answer: C. Digoxin toxicity

    Visual disturbances, GI upset, and arrhythmias are classic signs of digoxin toxicity.

58. A patient on warfarin recently started an antibiotic and now has bleeding gums. The most likely reason is that the antibiotic:

    1. A. Increased warfarin's anticoagulant effect
    2. B. Induced faster warfarin metabolism
    3. C. Caused vitamin K overload in the liver
    4. D. Chemically neutralized warfarin in the gut
    Show answer

    Answer: A. Increased warfarin's anticoagulant effect

    Antibiotics can increase warfarin's effect by inhibiting its metabolism or reducing vitamin K-producing gut flora. Many antibiotics raise the INR, increasing bleeding risk.

59. Rapid administration of a large IV dose of fentanyl can cause:

    1. A. Seizures from GABA receptor blockade
    2. B. Severe hypertension from catecholamine release
    3. C. Chest wall rigidity impairing ventilation
    4. D. Bronchodilation and reduced airway resistance
    Show answer

    Answer: C. Chest wall rigidity impairing ventilation

    Rigidity ('wooden chest') is associated with rapid high-dose fentanyl and may require a neuromuscular blocker or naloxone.

60. Itching and redness along the vein after IV morphine most often represent:

    1. A. Infiltration of the IV line
    2. B. Early serotonin syndrome
    3. C. Nonallergic histamine release
    4. D. True IgE-mediated anaphylaxis
    Show answer

    Answer: C. Nonallergic histamine release

    Morphine directly releases histamine; local flushing without systemic signs is not a true allergy.

61. Common, transient effects after adenosine include:

    1. A. Hyperglycemia and a prolonged sinus tachycardia
    2. B. Sustained hypertension with a severe occipital headache
    3. C. Prolonged hypotension lasting several hours afterward
    4. D. Flushing, chest discomfort, and brief asystole
    Show answer

    Answer: D. Flushing, chest discomfort, and brief asystole

    Adenosine's effects are brief because of its very short half-life; patients should be warned beforehand.

62. A patient taking dipyridamole requires adenosine. The interaction to anticipate is:

    1. A. An exaggerated adenosine effect
    2. B. A blocked adenosine effect
    3. C. A hypertensive crisis after the dose
    4. D. Faster clearance of adenosine
    Show answer

    Answer: A. An exaggerated adenosine effect

    Dipyridamole blocks adenosine uptake, prolonging and intensifying its effect, so a lower adenosine dose may be needed.

63. Theophylline or large amounts of caffeine may reduce adenosine's effect because they:

    1. A. Stimulate vagal tone
    2. B. Block adenosine receptors
    3. C. Increase adenosine metabolism in the liver
    4. D. Bind adenosine in the blood
    Show answer

    Answer: B. Block adenosine receptors

    Methylxanthines are adenosine receptor antagonists, so higher doses may be needed.

64. Sodium bicarbonate and calcium chloride given through the same IV line without flushing can:

    1. A. Cause a sudden rise in blood glucose
    2. B. Increase the absorption of calcium
    3. C. Neutralize each other into plain saline
    4. D. Form a calcium carbonate precipitate
    Show answer

    Answer: D. Form a calcium carbonate precipitate

    These drugs are incompatible; the line must be flushed between them.

65. A patient on a nonselective beta blocker has anaphylaxis that does not respond to repeated epinephrine. A recommended adjunct is:

    1. A. Glucagon
    2. B. Flumazenil
    3. C. Atropine alone
    4. D. Propranolol
    Show answer

    Answer: A. Glucagon

    Glucagon increases cardiac cAMP independently of the blocked beta receptors.

66. A patient on a nonselective beta blocker receives epinephrine. A possible result is:

    1. A. Exaggerated bronchodilation with marked tachycardia
    2. B. Severe hypertension from unopposed alpha effects
    3. C. Severe hypoglycemia from insulin release
    4. D. Profound hypotension from unopposed beta-2 vasodilation
    Show answer

    Answer: B. Severe hypertension from unopposed alpha effects

    With beta receptors blocked, epinephrine's alpha effects predominate, causing severe hypertension and reflex bradycardia.

67. Angioedema from an ACE inhibitor differs from allergic angioedema in that it:

    1. A. Is bradykinin-mediated rather than IgE-mediated
    2. B. Is always accompanied by widespread urticaria and itching
    3. C. Occurs only within hours of the very first dose
    4. D. Responds reliably to diphenhydramine given alone
    Show answer

    Answer: A. Is bradykinin-mediated rather than IgE-mediated

    ACE inhibition prevents bradykinin breakdown, so this angioedema may respond poorly to epinephrine and antihistamines; airway management is the priority.

68. A patient took a large acetaminophen overdose 3 hours ago and feels fine. This means:

    1. A. Activated charcoal is never indicated
    2. B. Significant toxicity has been ruled out
    3. C. Serious liver injury may still develop
    4. D. The patient can safely refuse evaluation
    Show answer

    Answer: C. Serious liver injury may still develop

    Early symptoms are often minimal; hepatotoxicity appears 24 to 72 hours later. Early treatment with N-acetylcysteine is most effective.

69. An acute dystonic reaction after prochlorperazine is commonly treated with:

    1. A. Ondansetron (Zofran)
    2. B. Naloxone (Narcan)
    3. C. Diphenhydramine
    4. D. Haloperidol (Haldol)
    Show answer

    Answer: C. Diphenhydramine

    Anticholinergic agents such as diphenhydramine or benztropine rapidly relieve drug-induced dystonia.

70. After a large dose of lidocaine, a patient reports a metallic taste, numbness around the mouth, and ringing in the ears. These findings suggest:

    1. A. A true IgE-mediated allergy to amide drugs
    2. B. Hypoglycemia from lidocaine
    3. C. Expected therapeutic effects
    4. D. Early local anesthetic toxicity
    Show answer

    Answer: D. Early local anesthetic toxicity

    These are early local anesthetic toxicity: rising lidocaine levels first cause CNS warning signs (perioral numbness, metallic taste, tinnitus, dizziness), then seizures and dysrhythmias: stop the drug and prepare to treat. A true IgE-mediated allergy to amide drugs is very rare and would cause hives or anaphylaxis, lidocaine does not cause hypoglycemia, and these are not expected therapeutic effects.

71. A patient develops a pounding headache a few minutes after sublingual nitroglycerin. This most likely represents:

    1. A. An allergic reaction to the nitrate tablets
    2. B. Evidence of nitrate tolerance
    3. C. Proof the tablets have expired
    4. D. An expected effect of vasodilation
    Show answer

    Answer: D. An expected effect of vasodilation

    Nitroglycerin dilates cerebral and meningeal vessels, so headache is a common, expected side effect and not by itself a reason to stop if blood pressure allows. It is not an allergic reaction to the nitrate tablets, tolerance would weaken rather than add effects, and a headache suggests the tablets are active rather than proof the tablets have expired.

72. A recognized adverse effect of ketamine is:

    1. A. Severe bradycardia with hypotension
    2. B. Chest wall rigidity during rapid push
    3. C. Emergence reactions such as hallucinations
    4. D. Pinpoint pupils with slowed respirations
    Show answer

    Answer: C. Emergence reactions such as hallucinations

    Emergence phenomena (hallucinations, agitation) and hypersalivation occur; ketamine usually maintains or raises heart rate and blood pressure.

73. During magnesium sulfate infusion, loss of deep tendon reflexes indicates:

    1. A. Ongoing seizure activity
    2. B. Early magnesium toxicity
    3. C. The safe therapeutic endpoint
    4. D. Hypocalcemia from low magnesium
    Show answer

    Answer: B. Early magnesium toxicity

    Loss of reflexes signals magnesium toxicity, which can progress to respiratory depression. Reflexes are lost before respiratory depression; calcium is the antidote.

74. St. John's wort can reduce the effect of drugs such as oral contraceptives and warfarin because it:

    1. A. Increases protein binding
    2. B. Blocks renal excretion
    3. C. Induces cytochrome P450 enzymes
    4. D. Inhibits cytochrome P450 enzymes
    Show answer

    Answer: C. Induces cytochrome P450 enzymes

    St. John's wort speeds metabolism of many drugs and can also contribute to serotonin syndrome.

75. A patient taking disulfiram drinks alcohol. The expected reaction includes:

    1. A. Severe hypoglycemia and seizures
    2. B. Flushing, vomiting, and headache
    3. C. Bradycardia with marked hypertension
    4. D. Pinpoint pupils and slow breathing
    Show answer

    Answer: B. Flushing, vomiting, and headache

    Disulfiram blocks aldehyde dehydrogenase, causing acetaldehyde to build up, with flushing, vomiting, headache, and possible hypotension. The reaction typically brings tachycardia rather than bradycardia, and blood pressure tends to fall rather than rise.

76. Giving rocuronium without adequate sedation risks:

    1. A. Hypertension from beta-2 receptor blockade
    2. B. Early return of spontaneous breathing efforts
    3. C. Malignant hyperthermia in most patients given it
    4. D. Awareness while the patient is paralyzed
    Show answer

    Answer: D. Awareness while the patient is paralyzed

    Neuromuscular blockers provide no sedation or analgesia, so a paralyzed patient may be awake and distressed; sedation must be maintained.

77. Combining albuterol and furosemide in a patient increases the risk of:

    1. A. Hypercalcemia
    2. B. Hyperkalemia
    3. C. Hypokalemia
    4. D. Hypernatremia
    Show answer

    Answer: C. Hypokalemia

    Albuterol shifts potassium into cells and furosemide increases its urinary loss.