A nurse is preparing to administer a loading dose of phenytoin 10 mg/kg by IV bolus to a client who weighs 154 lb. Available is phenytoin50 mg/mL. How many mL should the nurse administer? (Round the answer to the nearest whole number. Use a leading zero if it applies t use a trailing zero.)
The Correct Answer and Explanation is:
To determine the correct volume of phenytoin to administer, we need to follow these steps:
- Convert the Client’s Weight from Pounds to Kilograms: The client’s weight is given as 154 lb. To convert this to kilograms, use the conversion factor where 1 lb = 0.4536 kg.Weight in kg=154 lb×0.4536 kg/lb=69.85 kg\text{Weight in kg} = 154 \, \text{lb} \times 0.4536 \, \text{kg/lb} = 69.85 \, \text{kg}Weight in kg=154lb×0.4536kg/lb=69.85kg
- Calculate the Loading Dose: The loading dose is 10 mg/kg. Multiply the weight in kilograms by the dose in mg/kg.Loading Dose=69.85 kg×10 mg/kg=698.5 mg\text{Loading Dose} = 69.85 \, \text{kg} \times 10 \, \text{mg/kg} = 698.5 \, \text{mg}Loading Dose=69.85kg×10mg/kg=698.5mg
- Determine the Volume to Administer: Phenytoin is available at a concentration of 50 mg/mL. To find out how many mL are needed for the loading dose, divide the total dose required by the concentration of the drug.Volume=Loading DoseConcentration=698.5 mg50 mg/mL=13.97 mL\text{Volume} = \frac{\text{Loading Dose}}{\text{Concentration}} = \frac{698.5 \, \text{mg}}{50 \, \text{mg/mL}} = 13.97 \, \text{mL}Volume=ConcentrationLoading Dose=50mg/mL698.5mg=13.97mL
- Round the Volume to the Nearest Whole Number: The calculated volume is 13.97 mL. Rounding this to the nearest whole number gives 14 mL.
Summary: The nurse should administer 14 mL of phenytoin to achieve the loading dose. This calculation ensures that the client receives the correct amount of medication based on their weight and the available drug concentration.