An infant is to receive thyroxin sodium, 0.35 mg once a day orally. The medication is available in elixir form 0.25 mg/ml. How much elixir should the nurse administer?

1. A

   1.4 ml

2. B

   1.3 ml

3. C

   2.4 ml

4. D

   1.0 ml

Appeared in: OSSSC Nursing Officer-2023

Explanation

• determined using the standard formula for liquid medication calculation: (Dose Ordered / Dose on Hand) × Quantity.
• The dose ordered is 0.35 mg.
• The medication is available as an elixir with a concentration of 0.25 mg in 1 ml.
• Substituting the values into the formula: (0.35 mg / 0.25 mg) × 1 ml gives 1.4 ml.
• Accurate calculation is critical in pediatric populations to ensure therapeutic effectiveness and avoid toxicity.

Why Other Options Were Wrong

• Option B: This is an incorrect calculation. It may result from a simple mathematical error or misreading the prescribed dose or available concentration.
• Option C: This is a significant miscalculation, possibly from inverting the formula (i.e., dividing available by desired) or a decimal point error.
• Option D: This value would be correct only if the ordered dose was 0.25 mg, which matches the amount per ml of the elixir. It ignores the actual ordered dose of 0.35 mg.

Related Visual

Clinical Relevance

• Nursing practice connection: Knowing Pediatric Dosage Calculation helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
• Accurate dosage of thyroxine is vital for infants with congenital hypothyroidism to ensure normal brain development and physical growth. Underdosing can lead to developmental delays, while overdosing can cause symptoms of hyperthyroidism.
• Nurses must use appropriate measuring devices, like oral syringes, for pediatric liquid medications. Household spoons are inaccurate and should never be used.
• The principle of 'double-checking' calculations with another qualified nurse is a critical safety standard, especially for pediatric and high-alert medications.

How to Approach the Question

• First, identify the question type. This is an analytical (calculation) question.
• Identify the key pieces of information provided: the desired dose (D), the available dose or concentration (H), and the volume the available dose comes in (Q).
• Recall the standard dosage calculation formula: Volume = (D/H) x Q.
• Ensure all units are consistent. In this case, both the desired and available doses are in milligrams (mg), so no conversion is needed.
• Substitute the given values into the formula: (0.35 mg / 0.25 mg) x 1 ml.
• Perform the calculation and compare the result to the given options to find the correct answer.

Concept Tested & Keywords

• Concept Tested: Pediatric Dosage Calculation
• Stem keywords: infant, thyroxin sodium, 0.35 mg, elixir, 0.25 mg/ml
• Lead-in keywords: How much
• Clinical cues: The patient is an infant, which necessitates high accuracy in dosage calculation to prevent adverse effects.

Question ID

QR_oJHdOQiv6aZ-latNZNq

Copy ID

Reference Book

E6 Nursing Fundamentals Potter Perry 12e Part 3 pp. 141-143, 142-144

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 p. 1212-1214