Saunders NCLEX Dosage Calculations Test Bank (Latest Edition) — 2025 Comprehensive Nursing Math Review | Pediatric, IV Flow Rates, Reconstitution & Safe Medication Practice with Step-by-Step Rationales

Saunders Comprehensive Review for the NCLEX-PN®
Examination
9th Edition
• Author(s)Linda Anne Silvestri; Angela Silvestri


TEST BANK



1 — Weight-based (mg/kg) — pediatric antibiotic
Order: Ceftriaxone 50 mg/kg IV once.
Patient: 18 kg.
Supply: Vial contains 250 mg per 5 mL.
Question: How many mL will you draw and administer?
Work (dimensional analysis):
1. Calculate ordered dose (mg):
50 mg/kg × 18 kg = 900 mg.
2. Determine concentration (mg/mL):
250 mg ÷ 5 mL = 50 mg/mL.
3. Volume (mL) = desired ÷ concentration:
900 mg ÷ 50 mg/mL = 18.0 mL.
Final answer: 18.0 mL (round to 0.1 mL).

,Safety check / rationale: 50 mg/kg is within standard pediatric
dosing range for ceftriaxone (confirm allergy status and
compatibility). Verify patient weight in kg on chart and re-check
vial concentration. Common error: dividing 250 ÷ 5 incorrectly
(mistakes in mg/mL) or forgetting to multiply by kg.


2 — Weight-based (units/kg) — heparin bolus
Order: Heparin 80 units/kg IV bolus.
Patient: 25 kg.
Supply: Heparin 1000 units in 10 mL.
Question: How many mL will you give?
Work:
1. Dose (units) = 80 units/kg × 25 kg = 2000 units.
2. Concentration (units/mL) = 1000 units ÷ 10 mL = 100
units/mL.
3. Volume = 2000 units ÷ 100 units/mL = 20.0 mL.
Final answer: 20.0 mL.
Safety check / rationale: Heparin is high-alert — require
independent double-check before administration. Common
mistake: treating 1000 units/10 mL as 10 units/mL (decimal
shift) or using wrong unit conversion.


3 — Weight-based divided dosing (mg/kg/day)

,Order: Amoxicillin 45 mg/kg/day PO divided q8h (three
doses/day).
Patient: 70 kg.
Supply: Clinician must calculate single dose to be administered
q8h.
Question: What is the single dose (mg) per administration?
Work:
1. Total daily dose = 45 mg/kg × 70 kg = 3150 mg/day.
2. Divide by 3 (q8h) → single dose = 3150 mg ÷ 3 = 1050 mg.
Final answer: 1050 mg per dose (q8h).
Safety check / rationale: Verify max recommended adult doses;
check for renal impairment which may alter frequency.
Common incorrect approach: dividing by 2 (q12h) or forgetting
to multiply by kg first.


4 — Weight-based (mg/kg) — opioid
Order: Morphine 0.1 mg/kg IV once.
Patient: 22.5 kg.
Supply: Morphine 2 mg/mL.
Question: How many mL will you administer?
Work:
1. Dose (mg) = 0.1 mg/kg × 22.5 kg = 2.25 mg.
2. Volume (mL) = 2.25 mg ÷ (2 mg/mL) = 1.125 mL.

, 3. Round per facility: 1.1 mL (or 1.13 mL if syringe allows). I
recommend rounding to 1.1 mL (1 decimal) for practical
syringe measurement.
Final answer: 1.1 mL (rounded to nearest 0.1 mL).
Safety check / rationale: Opioids are high-alert; double-check
dose and calculate infusion/push rate. Common mistakes:
wrong decimal placement (e.g., giving 11.25 mL) — always
confirm mg → mL conversion.


5 — Weight-based (mg/kg) → concentration (mg/mL)
Order: Vancomycin 15 mg/kg IV q12h.
Patient: 82 kg.
Supply: Vancomycin prepared at 50 mg/mL (after
reconstitution/ dilution).
Question: How many mL per dose?
Work:
1. Dose = 15 mg/kg × 82 kg = 1230 mg.
2. Volume = 1230 mg ÷ 50 mg/mL = 24.6 mL.
Final answer: 24.6 mL (round to 0.1 mL).
Safety check / rationale: Verify trough/levels per protocol;
vancomycin is nephrotoxic—confirm renal function. Common
mistake: forgetting the mg/kg step or using mg → g conversion
incorrectly.