HESI RN Dosage Calculation (2) – Advanced Practice Questions for Exam Readiness

HESI RN Dosage Calculation (2)
Question 1:
A client with neuroleptic malignant syndrome receives a prescription for dantrolene 1.5
mg/kg IV. The client weighs 198 pounds. The label on 250 mg vial reads, "Reconstitute
with 5 mL sterile water for injection, USP. Reconstitution yields 50 mg/mL." How many
mg should the nurse administer? (Enter numeric value only.)

Explanation

Correct Answer (milligrams) : 135

Solution

Given: 1 kg = 2.2 lbs Client weighs 198 lbs

Step-by-Step Calculation:

1. Step 1: Convert weight from pounds to kilograms: Weight in kg = (Weight in lbs)
÷ (2.2 lbs/kg) Weight in kg = 198 ÷ 2.2 Weight in kg = 90 (rounded to the nearest
whole number)
2. Step 2: Calculate the required dosage in mg: Dosage = (Weight in kg) × (Dosage
in mg/kg) Dosage = 90 × 1.5 Dosage = 135

Therefore, the nurse should administer 135 mg of dantrolene.

Question 2:
The healthcare provider prescribes filgrastim 5 mcg/kg/day subcutaneously (SubQ) for a
client who weighs 132 pounds and has just completed chemotherapy. The medication is
available in 480 mcg/0.8 mL. How many mL should the nurse administer? (Enter
numerical value only. If rounding is required, round to the nearest tenth).

Explanation

Correct Answer (mL) : 0.5

Solution

Step 1:

Convert the client's weight from pounds to kilograms. 132 pounds ÷ 2.2 = 60 kilograms

Step 2:

,Calculate the total dose in mcg based on the client's weight. 5 mcg/kg × 60 kg = 300
mcg

Step 3:

Determine how many mL of medication to administer based on the available
concentration. (300 mcg) ÷ (480 mcg/0.8 mL) = (300 ÷ 480) × 0.8 (300 ÷ 480) = 0.625
0.625 × 0.8 = 0.5 mL

Result: The nurse should administer 0.5 mL of the medication.

Question 3:
The healthcare provider prescribes penicillin G benzathine 1,800,000 units intramuscular
(IM) for a client with a bacterial infection. The prefilled syringe is labeled, "Penicillin G
benzathine 1,200,000 units/2 mL." How many mL should the nurse administer to this
client? (Enter numerical value only, rounded to the nearest whole number.)

Explanation

Correct Answer (mL) : 3

Solution

Step 1: Determine the dosage required. 1,800,000 units

Step 2: Identify the concentration available. 1,200,000 units/2 mL

Step 3: Calculate the required volume. (1,800,000 ÷ 1,200,000) × 2 = 1.5 × 2 = 3 mL

Question 4:
The healthcare provider prescribes ampicillin 140 mg intravenously (IV) every 8 hours for
a child with meningitis. The vial is labeled, "Ampicillin 250 mg for reconstitution with 83
mL sterile normal saline for injection to yield a total solution concentration of 30 mg/mL."
How many mL should the nurse administer? (Enter the numeric value only. If rounding is
required, round to the nearest tenth.)

Correct Answer (mL) : 4.7

Solution

Step 1: Determine the dosage required. 140 mg

Step 2: Identify the concentration available. 30 mg/mL

, Step 3: Calculate the required volume. (140 ÷ 30) = 4.6667 Rounded to the nearest
tenth = 4.7 mL

Question 5:
The healthcare provider prescribes a loading dose of digoxin 0.6 mg intravenously (IV)
for a client with heart failure (HF). The nurse obtains digoxin injection 500 mcg in 2 mL
vial from the electronic medication system. How many mL should the nurse administer?
(Enter numeric value only. If rounding is required, round to the nearest tenth.)

Explanation

Correct Answer (mL) : 2.4

Solution

Step 1: Convert dosage from mg to mcg. 0.6 mg × 1000 = 600 mcg

Step 2: Identify the concentration available. 500 mcg/2 mL

Step 3: Calculate the required volume. (600 ÷ 500) × 2 = 1.2 × 2 = 2.4 mL




Question 6:
The nurse is preparing a client's dose of an IM analgesic in a single syringe. The
prescription is hydromorphone 4 mg and hydroxyzine 25 mg. The hydromorphone is
available in a 10 mg/mL ampule, and the hydroxyzine is available in a 50 mg/mL vial. How
many total mL should the nurse administer? (Enter the numeric value only. If rounding is
required, round to the nearest tenth.)

Explanation

Correct Answer (mL) : 0.9

Solution

Step 1: Calculate the hydromorphone volume required. 4 mg ÷ 10 mg/mL = 0.4 mL

Step 2: Calculate the hydroxyzine volume required. 25 mg ÷ 50 mg/mL = 0.5 mL

Step 3: Sum the volumes. 0.4 mL + 0.5 mL = 0.9 mL