NCLEX-RNPharmacological and Parenteral TherapiesHard
A client with a deep vein thrombosis is prescribed enoxaparin 1 mg/kg subcutaneously every 12 hours. The client weighs 176 lbs. The available concentration is enoxaparin 100 mg/mL. How many milliliters should the nurse administer per dose?
- A0.7 mL
- B0.8 mL
- C0.6 mL
- D0.9 mL
Show answer & explanationAnswer & explanation
Correct answer: B. 0.8 mL
First, convert the client's weight from pounds to kilograms: 176 lbs / 2.2 lbs/kg = 80 kg. Next, calculate the prescribed dose in mg: 80 kg x 1 mg/kg = 80 mg. Finally, calculate the volume to administer: (Desired Dose / Available Concentration) = 80 mg / 100 mg/mL = 0.8 mL. The nurse should administer 0.8 mL per dose.
Why the other options are wrong
- A. Incorrect calculation: (176/2.2)*1 / 100 = 0.8. This is 70mg/100mg/ml = 0.7ml, which is incorrect.
- C. Incorrect calculation: (176/2.2)*1 / 100 = 0.8. This is 60mg/100mg/ml = 0.6ml, which is incorrect.
- D. Incorrect calculation: (176/2.2)*1 / 100 = 0.8. This is 90mg/100mg/ml = 0.9ml, which is incorrect.
Weight-Based Dosage Calculation
Weight-based dosage calculation involves converting a client's weight to kilograms, then calculating the total dose in milligrams, and finally determining the volume to administer based on the available concentration.
- 1 kg = 2.2 lbs.
- Formula: (Weight in kg x Dose per kg) / Concentration = Volume.
- Always round client's weight to the nearest tenth or hundredth.
- Double-check all calculations, especially conversions.
Memory trick: Weight-KG, Dose-MG, Volume-ML: Convert, Calculate, Confirm.