RN Nursing · Dosage Calculation · Practice question
A 45-year-old male with bowel obstruction has been exhibiting signs of anxiety. The health care provider prescribes diazepam (Valium) 8 mg to be administered via the nasogastric tube three times a day. The medication available is 5 mg per 5 mL. How much milliliters (mL) of diazepam will the patient receive within 24 hours?
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✓
24 ml
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12 ml
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8 ml
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16 ml
Answer & explanation
Correct: 24 ml
This question requires two steps: first calculate the volume per dose, then multiply by the number of doses per day. The ordered dose is 8 mg, and the available concentration is 5 mg per 5 mL. Using the formula (Desired ÷ Have) × Volume: (8 mg ÷ 5 mg) × 5 mL = 1.6 × 5 = 8 mL per dose. The medication is ordered three times a day (every 8 hours), so the total daily volume is 8 mL × 3 = 24 mL. The correct answer is 24 mL over 24 hours. Option 12 mL might result from calculating two doses instead of three, or from a dose calculation error. Option 8 mL represents a single dose volume, not the 24-hour total. Option 16 mL would correspond to two doses of 8 mL each, misreading three times a day as twice a day. It is important to distinguish between per-dose calculations and total daily calculations, especially when the question specifically asks about a 24-hour period, as this question does. Medications given via nasogastric tube require the same precision as any other route.
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