Pharmacological and Parenteral Therapies 2 — Questions and Answers

Question 1: A nurse is preparing to administer digoxin (Lanoxin) 0.125 mg PO to a client with heart failure. Before administering the medication, which assessment is most critical?

Check the client's blood pressure
Assess the client's apical heart rate for one full minute (Correct answer)
Verify the client's last bowel movement
Assess the client's lung sounds

Correct answer: Assess the client's apical heart rate for one full minute

Digoxin slows the heart rate by increasing vagal tone. Before administration, the nurse must count the apical pulse for one full minute. If the heart rate is below 60 bpm in adults, digoxin is withheld and the provider is notified.

Digoxin is a cardiac glycoside used in heart failure and atrial fibrillation. It increases the force of cardiac contraction (positive inotropy) and slows conduction through the AV node (negative chronotropy), resulting in decreased heart rate. Due to its narrow therapeutic index (normal serum level 0.5-2.0 ng/mL; toxic at >2.0 ng/mL), digoxin requires careful pre-administration assessment. The most critical pre-administration check is the apical heart rate, counted for a full 60 seconds at the apex of the heart (5th intercostal space, midclavicular line). If the heart rate is below 60 bpm in adults, the nurse must withhold the dose and notify the provider. This is because digoxin can further slow an already bradycardic heart, leading to dangerous dysrhythmias or heart block. Other important monitoring for digoxin includes: checking serum digoxin levels and electrolytes (hypokalemia, hypomagnesemia, and hypercalcemia increase toxicity risk), monitoring for signs of toxicity (nausea, vomiting, visual disturbances such as yellow-green halos, bradycardia, dysrhythmias), and assessing renal function (digoxin is renally cleared — impaired kidneys increase drug accumulation). Blood pressure, lung sounds, and bowel habits are relevant assessments in heart failure but are not specific pre-administration safety checks for digoxin.

Question 2: A nurse is administering heparin as a continuous IV infusion. The order reads: Heparin 25,000 units in 250 mL D5W, infuse at 1,000 units/hour. At what rate should the nurse set the infusion pump (mL/hour)?

4 mL/hour
8 mL/hour
10 mL/hour (Correct answer)
25 mL/hour

Correct answer: 10 mL/hour

To calculate: concentration = 25,000 units / 250 mL = 100 units/mL. Rate = desired dose / concentration = 1,000 units/hour ÷ 100 units/mL = 10 mL/hour.

IV medication rate calculations are a critical nursing competency. The formula for calculating an infusion rate when given a dose per hour is: Step 1 — Calculate the concentration: Concentration = Total drug amount ÷ Total volume Concentration = 25,000 units ÷ 250 mL = 100 units/mL Step 2 — Calculate the infusion rate: Rate (mL/hour) = Desired dose (units/hour) ÷ Concentration (units/mL) Rate = 1,000 units/hour ÷ 100 units/mL = 10 mL/hour Verification: 10 mL/hour × 100 units/mL = 1,000 units/hour ✓ Heparin is a high-alert medication — calculation errors can cause dangerous bleeding or inadequate anticoagulation. Most facilities require two-nurse verification for heparin infusion setup and rate changes. The nurse should also monitor aPTT (activated partial thromboplastin time) according to the facility's heparin protocol, assess for bleeding (urine, stool, gingival, IV sites), and have protamine sulfate (heparin antidote) available. A common calculation error is inverting the formula (dividing concentration by dose) or using the wrong total volume. Dimensional analysis is an alternative calculation method that helps reduce errors by keeping track of units throughout the calculation.

Question 3: A nurse is caring for a client receiving morphine via patient-controlled analgesia (PCA). Which assessment finding requires immediate intervention?

Pain rating of 4/10 one hour after PCA initiation
Respiratory rate of 8 breaths per minute with pinpoint pupils (Correct answer)
Mild nausea reported 30 minutes after PCA initiation
Heart rate of 72 bpm and blood pressure 118/76 mmHg

Correct answer: Respiratory rate of 8 breaths per minute with pinpoint pupils

A respiratory rate of 8 breaths per minute with pinpoint pupils indicates opioid-induced respiratory depression and miosis — signs of opioid overdose. This requires immediate intervention including assessment, stopping the PCA, and administering naloxone (Narcan) per order.

Opioid-induced respiratory depression is the most dangerous complication of morphine and other opioids. Opioids bind to mu-receptors in the brainstem respiratory center, reducing respiratory drive. The combination of respiratory rate ≤10 breaths/minute and pinpoint pupils (miosis, due to opioid effect on the pupillary light reflex) are hallmark signs of opioid toxicity. Immediate nursing interventions for opioid respiratory depression include: (1) Stimulate the client — call their name, sternal rub if unresponsive. (2) Stop the PCA infusion immediately. (3) Administer supplemental oxygen. (4) Administer naloxone (Narcan) per standing order or emergency protocol (typically 0.4 mg IV/IM every 2-3 minutes, titrated to respiratory response — avoid full reversal to prevent acute pain crisis and withdrawal). (5) Notify the provider and prepare for possible transfer to higher level of care. (6) Monitor continuously — naloxone has a shorter half-life than most opioids and re-sedation can occur. Mild nausea is a common opioid side effect that warrants assessment and antiemetic therapy but is not an emergency. Pain of 4/10 requires reassessment and possible PCA adjustment. Normal vital signs are reassuring findings.

Question 4: A nurse is administering a peripheral IV infusion of potassium chloride (KCl) 40 mEq in 100 mL normal saline. The client reports burning and pain at the IV site. Which action should the nurse take first?

Slow the infusion rate
Apply a warm compress to the IV site
Assess the IV site for signs of infiltration (Correct answer)
Dilute the potassium with more normal saline

Correct answer: Assess the IV site for signs of infiltration

Before taking any corrective action, the nurse must first assess the IV site to determine whether the burning is due to normal vein irritation from the potassium or due to infiltration/extravasation, which requires the IV to be stopped immediately.

Potassium chloride is a highly caustic medication when administered intravenously. KCl causes significant vein irritation even when properly positioned in the vein (phlebitis), and it can cause serious tissue damage if it infiltrates into surrounding tissue (extravasation). Therefore, the nurse's first action must be to assess the IV site before taking any intervention. Assessment includes: inspecting the site for redness, swelling, or blanching (signs of infiltration), palpating for firmness or coolness of surrounding tissue, checking for blood return, and asking the client to describe the sensation (burning vs. sharp/pressure vs. aching). If infiltration is confirmed: stop the infusion immediately, remove the IV catheter, estimate the amount of extravasated fluid, apply warm compresses for KCl (to promote vasodilation and absorption), elevate the extremity, and notify the provider. A new IV access site should be established in a different extremity. If there is no infiltration and the discomfort is vein irritation (phlebitis from the potassium): the rate may be slowed if ordered, warm compresses may help, and the nurse assesses whether a higher concentration in a larger vein (central venous access) might be preferable. KCl concentration for peripheral IV should not exceed 10 mEq/100 mL per hour, and the infusion rate should not exceed 10-20 mEq/hour in most non-emergency situations.

Question 5: A nurse is preparing to administer insulin. The physician order reads: Regular insulin 10 units subcutaneously and NPH insulin 20 units subcutaneously. How should the nurse prepare this combined dose?

Draw up NPH first, then regular insulin into the same syringe
Draw up regular insulin first, then NPH insulin into the same syringe (Correct answer)
Administer each insulin in a separate syringe at separate sites
Mix both insulins in a vial and draw from the mixed vial

Correct answer: Draw up regular insulin first, then NPH insulin into the same syringe

When mixing regular and NPH insulin, the nurse draws regular (clear) insulin first, then NPH (cloudy) insulin. The mnemonic 'Clear before Cloudy' helps remember this sequence. Drawing regular insulin first prevents contamination with NPH.

Mixing regular and NPH insulin in the same syringe is a common nursing procedure that reduces the number of injections for the client. The correct sequence is essential to prevent contamination. Mnemonic: 'Clear before Cloudy' — Regular insulin is clear; NPH insulin is cloudy. Correct procedure: 1. Gather supplies (insulin vials, U-100 insulin syringe, alcohol swabs). 2. Inspect both vials for clarity, expiration, and correct concentration. 3. Roll (do not shake) the NPH vial to mix; regular insulin is clear and doesn't need mixing. 4. Inject air equal to the NPH dose into the NPH vial (without drawing up NPH) — withdraw the needle. 5. Inject air equal to the regular dose into the regular vial, then withdraw the regular (clear) insulin dose. 6. Insert the needle into the NPH vial and withdraw the NPH dose to the total combined dose. 7. Do not return any mixed insulin to either vial. If NPH is drawn first, NPH may be inadvertently injected into the regular insulin vial, altering the pharmacokinetic profile of the regular insulin. Separate syringes are acceptable but result in an extra injection. Creating a premixed vial is not an acceptable nursing practice.

Question 6: A nurse is caring for a client receiving vancomycin IV. The infusion is running over 60 minutes. Thirty minutes into the infusion, the client develops flushing, erythema, and pruritus of the face, neck, and upper torso. Which action should the nurse take first?

Administer diphenhydramine (Benadryl) as prescribed
Stop the infusion and notify the provider immediately
Slow the infusion rate (Correct answer)
Assess for anaphylaxis and prepare epinephrine

Correct answer: Slow the infusion rate

The described symptoms (flushing, erythema, pruritus of the face, neck, and upper torso) are classic signs of 'Red Man Syndrome,' a rate-related infusion reaction to vancomycin — not a true allergic reaction. The first intervention is to slow the infusion rate.

Red Man Syndrome is a well-known, rate-dependent adverse reaction to vancomycin caused by direct mast cell degranulation (not IgE-mediated) and histamine release. It is not a true allergic reaction or anaphylaxis. The hallmark presentation is flushing, erythema (redness), and pruritus distributed in a characteristic pattern across the face, neck, and upper torso — sometimes called the 'Red Man' distribution. Red Man Syndrome occurs when vancomycin is infused too rapidly (typically faster than 500 mg/30 minutes or 1,000 mg/60 minutes). The first-line intervention is to slow the infusion rate (not stop it). If symptoms are mild, reducing the rate to a slower pace (e.g., infusing 1g over 90-120 minutes) typically resolves the reaction. Diphenhydramine (Benadryl) may also be given to control the histamine response. Distinguishing Red Man Syndrome from anaphylaxis is critical: anaphylaxis presents with urticaria, bronchospasm, angioedema, hypotension, and/or cardiovascular collapse — not just flushing and erythema in a rate-related pattern. Anaphylaxis requires stopping the infusion and administering epinephrine. Prevention of Red Man Syndrome: administer vancomycin at ≤10 mg/min (e.g., 1g over ≥60 minutes). Premedication with diphenhydramine before infusion is used in clients with prior reactions.

Pharmacological and Parenteral Therapies 2

A nurse is preparing to administer digoxin (Lanoxin) 0.125 mg PO to a client with heart failure.
Before administering the medication, which assessment is most critical?