NAPLEX Quiz: Parenteral Medications

What this quiz covers

This quiz focuses on Parenteral Medications, 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. Continue levofloxacin 750 mg IV every 24 hours (no adjustment needed)
2. Change to levofloxacin 750 mg IV every 48 hours (correct answer)
3. Change to levofloxacin 250 mg IV every 24 hours
4. Change to levofloxacin 500 mg IV every 8 hours

Explanation: This question tests knowledge of fluoroquinolone dosing adjustments in severe renal impairment. The patient has a creatinine clearance of 22 mL/min, which requires significant dose adjustment for levofloxacin to prevent accumulation and toxicity. For severe pneumonia, levofloxacin 750 mg is typically given daily, but with CrCl 20-49 mL/min, the interval should be extended to every 48 hours while maintaining the 750 mg dose. Option A (no adjustment) would lead to drug accumulation and increased risk of QT prolongation and CNS effects. Option C reduces the dose too much and would be suboptimal for pneumonia treatment. Option D increases frequency inappropriately and would worsen toxicity risk. The clinical pearl is that fluoroquinolones require interval extension (not dose reduction) in renal impairment to maintain adequate peak concentrations while preventing accumulation.

Question 2

1. Increase potassium, magnesium, and phosphate in the TPN and recommend thiamine supplementation due to refeeding risk (correct answer)
2. Hold all electrolytes in the TPN for the first 48 hours to avoid osmolarity issues
3. Add calcium chloride and phosphate at high doses in the same TPN to rapidly correct deficits
4. Start lipid emulsion at maximum dose and omit dextrose to prevent hyperglycemia

Explanation: This question addresses refeeding syndrome prevention in a malnourished patient starting TPN. The patient has multiple electrolyte deficiencies (low potassium, magnesium, and phosphate) and has been NPO for 7 days, placing him at high risk for refeeding syndrome. The correct approach is to replete electrolytes in the TPN and supplement thiamine before aggressive nutrition support to prevent cardiac and neurologic complications. Holding all electrolytes (option B) would worsen deficiencies and increase refeeding risk. Adding calcium chloride and phosphate together (option C) would cause precipitation and is incompatible. Starting maximum lipids while omitting dextrose (option D) doesn't address the electrolyte issues and could worsen the metabolic state. The clinical pearl is that malnourished patients require electrolyte repletion and thiamine supplementation before initiating aggressive nutrition support to prevent potentially fatal refeeding syndrome.

Question 3

1. Vitamin K 10 mg IV plus 4-factor prothrombin complex concentrate (PCC) dosed by INR and weight (correct answer)
2. Vitamin K 1 mg IV only, then recheck INR in 24 hours
3. Fresh frozen plasma (FFP) only, no vitamin K, because PCC provides no benefit
4. Protamine sulfate IV to reverse warfarin anticoagulation

Explanation: This question tests knowledge of urgent warfarin reversal in life-threatening bleeding. The patient has a supratherapeutic INR (6.2) with active GI bleeding and hemodynamic instability requiring immediate reversal. The combination of vitamin K 10 mg IV plus 4-factor PCC provides the fastest and most complete reversal, with PCC working within minutes and vitamin K sustaining the reversal. Vitamin K alone (option B) takes 12-24 hours for effect, which is too slow for urgent reversal. FFP alone (option C) requires large volumes, takes longer to administer, and is less effective than PCC. Protamine (option D) reverses heparin, not warfarin. The key principle is that life-threatening warfarin-associated bleeding requires both immediate reversal with PCC and sustained reversal with vitamin K for optimal outcomes.

Question 4

1. Administer acyclovir as a rapid IV push to achieve higher CNS concentrations
2. Ensure renal dose adjustment and adequate IV hydration to reduce risk of crystal nephropathy (correct answer)
3. Avoid any IV fluids to prevent worsening kidney function
4. Switch to topical acyclovir because systemic therapy is not needed for encephalitis

Explanation: This question tests the concept of preventing nephrotoxicity with acyclovir in renal impairment. The key patient-specific factor is the patient's chronic kidney disease with SCr 2.8 mg/dL, increasing risk for crystal nephropathy. Option B is the best choice because dose adjustment (e.g., 10 mg/kg q24h) and hydration reduce crystal formation and maintain efficacy. Option A is incorrect as rapid push increases nephrotoxicity; option C is suboptimal as fluids are needed to prevent crystals; option D is inappropriate as topical acyclovir is ineffective for encephalitis. Adjust acyclovir dose by CrCl and infuse over 1 hour with hydration. A decision framework is to monitor urine output and SCr daily during therapy.

Question 5

1. Diazepam continuous IV infusion due to long half-life in liver disease
2. Lorazepam IV (intermittent or infusion) because it is less dependent on hepatic oxidation (correct answer)
3. Midazolam IV only because lorazepam is contraindicated with elevated AST/ALT
4. Chlordiazepoxide IV because it is first-line for all severe withdrawal

Explanation: This question tests the concept of benzodiazepine selection in alcohol withdrawal with hepatic impairment. The key patient-specific factor is the patient's elevated liver enzymes, affecting metabolism of certain benzodiazepines. Option B is the best choice because lorazepam undergoes glucuronidation, which is less impaired in liver disease, making it safer for intermittent or continuous use. Option A is incorrect as diazepam has prolonged half-life in cirrhosis; option C is suboptimal as midazolam is hepatically oxidized; option D is inappropriate as chlordiazepoxide is oral and hepatically metabolized. Prefer lorazepam or oxazepam in hepatic dysfunction for withdrawal. A clinical pearl is to use CIWA-Ar scores to guide symptom-triggered dosing.

Question 6

1. Continue heparin and recheck platelets in 1 week because this is expected
2. Stop heparin and recommend evaluation for heparin-induced thrombocytopenia with initiation of a non-heparin anticoagulant (correct answer)
3. Add warfarin immediately as monotherapy and stop heparin now
4. Administer vitamin K 10 mg IV now to reverse heparin

Explanation: This question tests the concept of recognizing and managing heparin-induced thrombocytopenia (HIT). The key patient-specific factor is the significant platelet drop (>50%) and new bruising after 5 days of heparin, suggestive of HIT. Option B is the best choice because stopping heparin and starting a non-heparin anticoagulant (e.g., argatroban) prevents thrombosis while evaluating with HIT assays. Option A is incorrect as continuing heparin risks severe complications; option C is suboptimal as warfarin alone increases thrombosis in acute HIT; option D is inappropriate as vitamin K does not reverse heparin. Calculate 4T score for HIT suspicion and confirm with assays. A clinical pearl is to avoid all heparins in suspected HIT and use direct thrombin inhibitors.

Question 7

1. Recommend a separate IV line (or dedicated lumen) for amiodarone and avoid Y-site co-infusion with furosemide due to incompatibility risk (correct answer)
2. Approve Y-site co-infusion because both are clear solutions and therefore compatible
3. Recommend mixing furosemide directly into the amiodarone infusion bag to simplify administration
4. Switch amiodarone to IV push dosing so furosemide can run continuously

Explanation: This question evaluates knowledge of IV drug compatibility and safe administration practices. Amiodarone and furosemide are incompatible when co-infused through the same line due to precipitation risk, which could cause catheter occlusion or embolism. The safest approach is to use a separate IV line or dedicated lumen for amiodarone to avoid any compatibility issues. Simply having clear solutions (option B) doesn't guarantee compatibility. Mixing drugs directly in the same bag (option C) is dangerous and could cause immediate precipitation. IV push amiodarone (option D) is only used in cardiac arrest situations and doesn't solve the compatibility issue. The clinical principle is that IV drug compatibility must be verified before Y-site administration, and when in doubt, separate lines should be used to ensure patient safety.

Question 8

1. Ensure appropriate premedication (e.g., corticosteroid, H1 blocker, and H2 blocker) is ordered to reduce hypersensitivity reactions (correct answer)
2. Add leucovorin rescue starting 24 hours after paclitaxel to prevent mucositis
3. Avoid any premedication to prevent masking early signs of an infusion reaction
4. Administer paclitaxel as an IV push to reduce infusion reaction risk

Explanation: This question tests knowledge of chemotherapy premedication protocols to prevent hypersensitivity reactions. Paclitaxel is formulated with Cremophor EL, which frequently causes hypersensitivity reactions including anaphylaxis. Standard premedication includes a corticosteroid (dexamethasone), H1 blocker (diphenhydramine), and H2 blocker (famotidine or ranitidine) given before infusion to significantly reduce reaction risk. Leucovorin rescue (option B) is used with methotrexate, not paclitaxel. Avoiding premedication (option C) would be dangerous given the high reaction risk. IV push administration (option D) would increase reaction risk and is never appropriate for paclitaxel. The key principle is that taxane chemotherapy requires specific premedication protocols to prevent potentially life-threatening hypersensitivity reactions, especially in patients with a history of drug reactions.

Question 9

1. Epinephrine 0.3 mg intramuscularly (1 mg/mL) in the mid-outer thigh, repeat every 5–15 minutes as needed (correct answer)
2. Diphenhydramine 25 mg IV as the sole initial therapy
3. Methylprednisolone 125 mg IV as the sole initial therapy
4. Epinephrine 0.3 mg IV push (1 mg/10 mL) immediately

Explanation: This question evaluates emergency management of anaphylaxis with appropriate epinephrine administration. The patient presents with classic anaphylaxis symptoms (wheezing and hypotension after bee sting) requiring immediate epinephrine. The correct dose is 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) given intramuscularly in the mid-outer thigh, which provides rapid absorption and effect. Diphenhydramine alone (option B) or methylprednisolone alone (option C) are inadequate as they don't reverse bronchospasm or hypotension acutely. IV push epinephrine at 1:1000 concentration (option D) would deliver 10 times the appropriate dose and could cause severe hypertension, arrhythmias, or stroke. The clinical pearl is that IM epinephrine (1:1000) in the thigh is first-line for anaphylaxis, while IV epinephrine requires 1:10,000 dilution and is reserved for cardiac arrest or refractory shock.

Question 10

1. Serum potassium and magnesium frequently with supplementation as needed (correct answer)
2. INR every 12 hours
3. Troponin every 6 hours
4. Serum lipase daily

Explanation: This question tests the concept of electrolyte monitoring during amphotericin B therapy. The key patient-specific factor is the patient's baseline hypokalemia and hypomagnesemia, which amphotericin exacerbates via renal wasting. Option A is the best choice because frequent potassium and magnesium checks with repletion prevent arrhythmias and other complications. Option B is incorrect as INR is unaffected; option C is suboptimal as troponin is for cardiac injury; option D is inappropriate as lipase is unrelated. Monitor electrolytes daily and replete aggressively with amphotericin. A decision framework is to use liposomal formulations to reduce nephrotoxicity but still monitor closely.

Question 11

1. Administer alteplase immediately; blood pressure control can occur after infusion
2. Lower blood pressure to recommended thresholds before alteplase administration to reduce bleeding risk (correct answer)
3. Administer vitamin K IV prior to alteplase
4. Administer alteplase as an IV push only (no infusion) to reduce time to treatment

Explanation: This question tests the concept of blood pressure management prior to thrombolysis in acute ischemic stroke. The key patient-specific factor is the elevated blood pressure of 198/112 mmHg, which increases intracranial hemorrhage risk with alteplase. Option B is the best choice because lowering BP to <185/110 mmHg before and <180/105 mmHg after alteplase minimizes bleeding per guidelines. Option A is incorrect as uncontrolled BP contraindicates thrombolysis; option C is suboptimal as vitamin K is for anticoagulants; option D is inappropriate as alteplase requires bolus plus infusion. Control BP with IV agents like labetalol before thrombolysis. A clinical pearl is to adhere to AHA time windows and exclusion criteria for safe alteplase use.

Question 12

1. Cefepime neurotoxicity is unlikely; increase the dose to improve pneumonia coverage
2. Assess for cefepime accumulation due to renal impairment and recommend renal dose adjustment or alternative therapy (correct answer)
3. Add diphenhydramine IV to treat presumed allergy-related symptoms
4. Switch to oral cefepime immediately because oral therapy prevents neurotoxicity

Explanation: This question tests the recognition of antibiotic-induced neurotoxicity in the context of parenteral medications. The key patient-specific factor is the elevated serum creatinine (SCr 2.6 mg/dL) and BUN (55 mg/dL), indicating renal impairment that affects cefepime clearance. Assessing for cefepime accumulation due to renal impairment and recommending dose adjustment or alternative therapy is the best choice because cefepime is primarily renally excreted, and accumulation can lead to neurotoxic effects like confusion and myoclonus. Increasing the dose is incorrect as it would worsen potential accumulation and neurotoxicity without addressing the underlying renal issue, while adding diphenhydramine assumes an allergic reaction, which is unlikely given the symptoms and lack of allergy history. Switching to oral cefepime is suboptimal because oral formulations are not equivalent for severe infections like hospital-acquired pneumonia and do not inherently prevent neurotoxicity. A key clinical pearl is that beta-lactam antibiotics like cefepime require renal dose adjustments to prevent adverse effects in patients with impaired kidney function. Always calculate creatinine clearance using tools like Cockcroft-Gault to guide dosing decisions in such scenarios.

Question 13

1. Blood glucose monitoring for hypoglycemia (correct answer)
2. INR monitoring for bleeding
3. Serum vancomycin trough concentration
4. Absolute neutrophil count

Explanation: This question evaluates monitoring requirements for emergency treatment of hyperkalemia using parenteral medications. The key patient-specific factor is the administration of insulin with dextrose to shift potassium intracellularly, alongside the patient's baseline glucose of 160 mg/dL. Blood glucose monitoring for hypoglycemia is the best choice because insulin can rapidly lower blood sugar, potentially causing symptomatic hypoglycemia if not monitored closely. INR monitoring for bleeding is incorrect as there are no anticoagulants involved, and serum vancomycin trough is irrelevant since vancomycin is not being administered. Absolute neutrophil count is suboptimal as it does not relate to the acute effects of insulin-dextrose therapy. A transferable clinical pearl is that insulin-dextrose for hyperkalemia should include point-of-care glucose checks every 30-60 minutes for at least 4 hours post-administration. In decision-making, prioritize monitoring for the most immediate and predictable adverse effect of the intervention being used.

Question 14

1. Change to piperacillin-tazobactam 3.375 g IV every 6 hours (no adjustment needed)
2. Change to piperacillin-tazobactam 3.375 g IV every 8 hours
3. Change to piperacillin-tazobactam 2.25 g IV every 8 hours (correct answer)
4. Change to piperacillin-tazobactam 4.5 g IV every 6 hours

Explanation: This question evaluates piperacillin-tazobactam dosing in severe renal impairment. The patient has a CrCl of 18 mL/min, which requires significant dose adjustment to prevent accumulation of both piperacillin and tazobactam. For CrCl <20 mL/min, the recommended dose is 2.25 g every 8 hours (or every 6 hours for Pseudomonas). Option A (no adjustment) would lead to significant drug accumulation and increased risk of neurotoxicity including seizures. Option B reduces frequency but maintains too high a dose. Option D increases the dose inappropriately. The key principle is that beta-lactam/beta-lactamase inhibitor combinations require both dose and interval adjustments in severe renal impairment, with more aggressive reductions needed when CrCl falls below 20 mL/min to prevent CNS toxicity.

Question 15

1. Epinephrine 0.3 mg intramuscularly in the anterolateral thigh now (correct answer)
2. Epinephrine 1 mg IV push now
3. Diphenhydramine 50 mg IV now as the primary treatment
4. Methylprednisolone 125 mg IV now as the primary treatment

Explanation: This question tests the concept of emergency management of anaphylaxis with appropriate epinephrine administration. The key patient-specific factor is the patient's hypotension and wheezing, indicating severe anaphylaxis requiring rapid intervention. Option A is the best choice because intramuscular epinephrine 0.3 mg in the thigh provides quick absorption and is first-line for anaphylaxis without IV access issues. Option B is incorrect as IV epinephrine 1 mg is for cardiac arrest, not anaphylaxis; option C is suboptimal as diphenhydramine is adjunctive, not primary; option D is inappropriate as steroids are supportive but not immediate. In anaphylaxis, prioritize epinephrine IM followed by adjuncts like H1 blockers. A clinical pearl is to administer epinephrine early to prevent progression to shock.

Question 16

1. Prochlorperazine 10 mg IV once with diphenhydramine 25 mg IV once (correct answer)
2. Metoclopramide 10 mg IV once
3. Hydromorphone 2 mg IV once as first-line migraine therapy
4. Ergotamine IV continuous infusion

Explanation: This question tests the concept of IV abortive therapy for acute migraine in patients with contraindications. The key patient-specific factor is the patient's allergy to metoclopramide, necessitating an alternative antiemetic with diphenhydramine to prevent dystonia. Option A is the best choice because prochlorperazine with diphenhydramine effectively treats migraine without the akathisia risk of metoclopramide. Option B is incorrect due to the allergy; option C is suboptimal as opioids are not first-line; option D is inappropriate as ergotamine risks vasoconstriction. Use neuroleptics with anticholinergics for migraine when triptans fail. A decision framework is to assess allergies and use evidence-based IV options like prochlorperazine.

Question 17

1. Allow Y-site administration because ceftriaxone is compatible with all calcium salts
2. Avoid co-administration; use separate lines or thoroughly flush between ceftriaxone and calcium-containing solutions (correct answer)
3. Switch ceftriaxone to cefazolin IV without assessing culture results
4. Administer calcium chloride IV push via peripheral line to minimize delay

Explanation: This question tests the concept of IV drug compatibility, specifically the ceftriaxone-calcium interaction. The key patient-specific factor is the patient's hypocalcemia requiring IV calcium gluconate while on ceftriaxone. Option B is the best choice because avoiding co-administration and flushing lines prevents precipitate formation, which can cause serious adverse events like embolization. Option A is incorrect as ceftriaxone is incompatible with calcium; option C is suboptimal without need, as ceftriaxone is appropriate; option D is dangerous as peripheral calcium chloride causes tissue necrosis. Always check for known incompatibilities like ceftriaxone-calcium in adults. A clinical pearl is to separate administration by at least 1 hour if using the same line.

Question 18

1. Start TPN with standard electrolytes and correct potassium, magnesium, and phosphate after 48 hours
2. Hold IV lipid emulsion initially and replete electrolytes aggressively due to refeeding risk and hypertriglyceridemia (correct answer)
3. Add insulin to the TPN bag at 1 unit per gram of dextrose to normalize glucose immediately
4. Use peripheral parenteral nutrition at full caloric needs to avoid central line complications

Explanation: This question tests the concept of safe initiation of total parenteral nutrition (TPN) in patients at risk for refeeding syndrome. The key patient-specific factor is the patient's electrolyte imbalances, hypertriglyceridemia, and risk for refeeding due to acute pancreatitis and malnutrition. Option B is the best choice because holding lipids initially prevents worsening hypertriglyceridemia, and aggressive electrolyte repletion mitigates refeeding syndrome risks like hypophosphatemia. Option A is incorrect as delaying repletion increases arrhythmia risk; option C is suboptimal as adding insulin to TPN is not standard without hyperglycemia control protocols; option D is inappropriate as peripheral nutrition cannot meet full caloric needs without risking phlebitis. For TPN initiation, assess refeeding risk factors like low electrolytes and start conservatively with monitoring. A clinical pearl is to replete phosphate, potassium, and magnesium before or during TPN to prevent severe complications.

Question 19

1. Recommend obtaining a random gentamicin level 30 minutes after the first dose
2. Recommend extended-interval dosing only if SCr is < 1.0 mg/dL
3. Recommend individualized dosing and therapeutic drug monitoring with a level-based interval adjustment due to renal impairment (correct answer)
4. Switch to oral gentamicin to avoid nephrotoxicity

Explanation: This question tests the concept of therapeutic drug monitoring for aminoglycosides in renal impairment to optimize efficacy and minimize toxicity. The key patient-specific factor is the patient's elevated SCr of 1.9 mg/dL, indicating reduced clearance and risk for gentamicin accumulation. Option C is the best choice because individualized dosing with level monitoring allows interval adjustments to achieve target peaks/troughs, reducing nephrotoxicity risk. Option A is incorrect as random levels are not standard for extended-interval dosing; option B is suboptimal as extended-interval can be used in mild impairment with monitoring; option D is inappropriate as oral gentamicin has poor bioavailability. For aminoglycosides, use pharmacokinetic calculations and levels to guide therapy in renal dysfunction. A clinical pearl is to aim for troughs <1 mg/L in traditional dosing to prevent ototoxicity and nephrotoxicity.

Question 20

1. Serum potassium and daily weights/urine output (correct answer)
2. INR every 6 hours
3. Absolute neutrophil count daily
4. Serum amylase and lipase daily

Explanation: This question tests the concept of monitoring for electrolyte imbalances and fluid status during IV diuretic therapy. The key patient-specific factor is the patient's hyperkalemia, hyponatremia, and renal impairment in the setting of heart failure exacerbation. Option A is the best choice because IV furosemide can cause hypokalemia and fluid shifts, necessitating close monitoring of potassium, weights, and urine output to guide therapy and prevent dehydration. Option B is incorrect as INR is not directly affected by furosemide; option C is suboptimal as neutropenia is not a common side effect; option D is inappropriate as amylase/lipase are unrelated to diuretic monitoring. In diuretic therapy, establish baseline electrolytes and monitor daily to adjust dosing. A decision framework is to balance diuresis with electrolyte replacement to avoid arrhythmias or worsening renal function.