Chapter 1 —Medication Orders & Tablet
Calculations
Stem: An order reads: Morphine 0.25 mg IV now. The vial on
the cart is labeled 1 mg/mL. How many mL will you administer?
A. 0.025 mL
B. 0.25 mL
C. 0.5 mL
D. 2.5 mL
Correct Answer: B
Rationale (Correct):
Goal: find mL to deliver 0.25 mg when concentration = 1 mg per
1 mL.
,Step 1: Use formula: volume (mL) = desired dose (mg) ÷
concentration (mg/mL).
Step 2: 0.25 mg ÷ 1 mg/mL = 0.25 mL.
Principle: divide desired dose by concentration.
Rationale (Incorrects):
A (0.025 mL): decimal moved one place left — reflects a
decimal placement error (tenfold underdose).
C (0.5 mL): equals 0.5 mg given (twice the ordered dose) —
reflects doubling the intended volume.
D (2.5 mL): equals 2.5 mg — reflects moving decimal two places
(1000% error).
Teaching Point: Always divide desired dose by concentration;
watch decimal placement carefully.
2. Chapter 1 — Section 1.2: Weight-Based Dosing & Unit
Conversion
Stem: Pediatric order: Amoxicillin 10 mg/kg PO single dose.
Child weighs 33 lb. How many mg will you give?
A. 150 mg
B. 300 mg
C. 330 mg
D. 1500 mg
Correct Answer: B
Rationale (Correct):
Step 1: Convert pounds to kilograms: 33 lb ÷ 2.2 = 15 kg (exactly
,15.0 kg).
Step 2: Dose = 10 mg/kg × 15 kg = 150 mg? — careful: 10 mg/kg
× 15 kg = 150 mg. Wait options — check arithmetic: 33 lb ÷ 2.2
= 15 kg; 10 × 15 = 150. The correct numeric choice is A.
(Correction: correct answer should be A. I mis-selected above.)
Correction — Final Correct Answer: A
Corrected Rationale (Correct):
33 lb ÷ 2.2 = 15.0 kg.
10 mg/kg × 15.0 kg = 150 mg.
Principle: always convert weight to kg before dose calculation.
Rationale (Incorrects):
B (300 mg): reflects doubling (possibly using 20 mg/kg instead
of 10 mg/kg).
C (330 mg): reflects using pounds directly (10 × 33 = 330 mg) —
failure to convert lb → kg.
D (1500 mg): decimal place error (10× greater than 150 mg).
Teaching Point: Convert pounds to kilograms before weight-
based dosing.
3. Chapter 1 — Section 1.3: IV Infusion Rate (mL/hr) — Basic
Calculation
Stem: Order: Ceftriaxone 1 g in 250 mL IV to infuse over 2
hours. What mL/hr should you program?
A. 100 mL/hr
B. 125 mL/hr
, C. 150 mL/hr
D. 250 mL/hr
Correct Answer: B
Rationale (Correct):
Volume = 250 mL; Time = 2 hours. Rate (mL/hr) = 250 mL ÷ 2 hr
= 125 mL/hr.
Rationale (Incorrects):
A (100 mL/hr): reflects dividing 250 by 2.5 hours or wrong time.
C (150 mL/hr): reflects dividing by 1.67 hr (incorrect) or
rounding up incorrectly.
D (250 mL/hr): would infuse in 1 hour (twice the intended
infusion rate).
Teaching Point: mL/hr = total volume ÷ total hours; program
pumps precisely.
4. Chapter 1 — Section 1.3: Drip Rate (gtt/min) with Drop
Factor
Stem: An order: Infuse 150 mL D5W over 3 hours. The tubing is
60 gtt/mL. What is the drops/min (gtt/min)?
A. 25 gtt/min
B. 33 gtt/min
C. 50 gtt/min
D. 75 gtt/min
Correct Answer: C
Calculations
Stem: An order reads: Morphine 0.25 mg IV now. The vial on
the cart is labeled 1 mg/mL. How many mL will you administer?
A. 0.025 mL
B. 0.25 mL
C. 0.5 mL
D. 2.5 mL
Correct Answer: B
Rationale (Correct):
Goal: find mL to deliver 0.25 mg when concentration = 1 mg per
1 mL.
,Step 1: Use formula: volume (mL) = desired dose (mg) ÷
concentration (mg/mL).
Step 2: 0.25 mg ÷ 1 mg/mL = 0.25 mL.
Principle: divide desired dose by concentration.
Rationale (Incorrects):
A (0.025 mL): decimal moved one place left — reflects a
decimal placement error (tenfold underdose).
C (0.5 mL): equals 0.5 mg given (twice the ordered dose) —
reflects doubling the intended volume.
D (2.5 mL): equals 2.5 mg — reflects moving decimal two places
(1000% error).
Teaching Point: Always divide desired dose by concentration;
watch decimal placement carefully.
2. Chapter 1 — Section 1.2: Weight-Based Dosing & Unit
Conversion
Stem: Pediatric order: Amoxicillin 10 mg/kg PO single dose.
Child weighs 33 lb. How many mg will you give?
A. 150 mg
B. 300 mg
C. 330 mg
D. 1500 mg
Correct Answer: B
Rationale (Correct):
Step 1: Convert pounds to kilograms: 33 lb ÷ 2.2 = 15 kg (exactly
,15.0 kg).
Step 2: Dose = 10 mg/kg × 15 kg = 150 mg? — careful: 10 mg/kg
× 15 kg = 150 mg. Wait options — check arithmetic: 33 lb ÷ 2.2
= 15 kg; 10 × 15 = 150. The correct numeric choice is A.
(Correction: correct answer should be A. I mis-selected above.)
Correction — Final Correct Answer: A
Corrected Rationale (Correct):
33 lb ÷ 2.2 = 15.0 kg.
10 mg/kg × 15.0 kg = 150 mg.
Principle: always convert weight to kg before dose calculation.
Rationale (Incorrects):
B (300 mg): reflects doubling (possibly using 20 mg/kg instead
of 10 mg/kg).
C (330 mg): reflects using pounds directly (10 × 33 = 330 mg) —
failure to convert lb → kg.
D (1500 mg): decimal place error (10× greater than 150 mg).
Teaching Point: Convert pounds to kilograms before weight-
based dosing.
3. Chapter 1 — Section 1.3: IV Infusion Rate (mL/hr) — Basic
Calculation
Stem: Order: Ceftriaxone 1 g in 250 mL IV to infuse over 2
hours. What mL/hr should you program?
A. 100 mL/hr
B. 125 mL/hr
, C. 150 mL/hr
D. 250 mL/hr
Correct Answer: B
Rationale (Correct):
Volume = 250 mL; Time = 2 hours. Rate (mL/hr) = 250 mL ÷ 2 hr
= 125 mL/hr.
Rationale (Incorrects):
A (100 mL/hr): reflects dividing 250 by 2.5 hours or wrong time.
C (150 mL/hr): reflects dividing by 1.67 hr (incorrect) or
rounding up incorrectly.
D (250 mL/hr): would infuse in 1 hour (twice the intended
infusion rate).
Teaching Point: mL/hr = total volume ÷ total hours; program
pumps precisely.
4. Chapter 1 — Section 1.3: Drip Rate (gtt/min) with Drop
Factor
Stem: An order: Infuse 150 mL D5W over 3 hours. The tubing is
60 gtt/mL. What is the drops/min (gtt/min)?
A. 25 gtt/min
B. 33 gtt/min
C. 50 gtt/min
D. 75 gtt/min
Correct Answer: C
