A nurse is preparing to administer pentamidine 4 mg/kg IM to a client who weighs 154 lb

A nurse is preparing to administer pentamidine 4 mg/kg IM to a client who weighs 154 lb. Available is pentamidine 100 mg/mL for injection. How many mL should the nurse administer? (Round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero.)

To calculate the dose of pentamidine in milliliters (mL) that the nurse should administer, we can use the following steps:

The correct answer and Explanation is :

To calculate the dose of pentamidine in milliliters (mL) that the nurse should administer, follow these steps:

1. Convert the Client’s Weight to Kilograms:
   The client’s weight is given in pounds (lb), and the dosage of pentamidine is specified in mg/kg. Therefore, we need to convert the weight from pounds to kilograms. [
   \text{Weight in kg} = \text{Weight in lb} \times \frac{1 \text{ kg}}{2.2046 \text{ lb}}
   ] For a client weighing 154 lb: [
   \text{Weight in kg} = 154 \times \frac{1}{2.2046} \approx 70 \text{ kg}
   ]
2. Calculate the Required Dose of Pentamidine in mg:
   The ordered dose is 4 mg/kg. Therefore, multiply the client’s weight in kg by the dose per kg: [
   \text{Dose in mg} = \text{Weight in kg} \times \text{Dose per kg}
   ] [
   \text{Dose in mg} = 70 \times 4 = 280 \text{ mg}
   ]
3. Determine the Volume of Pentamidine Solution Required:
   The available solution concentration is 100 mg/mL. To find out how many mL are needed to administer 280 mg, use the formula: [
   \text{Volume in mL} = \frac{\text{Dose in mg}}{\text{Concentration in mg/mL}}
   ] [
   \text{Volume in mL} = \frac{280 \text{ mg}}{100 \text{ mg/mL}} = 2.8 \text{ mL}
   ]

So, the nurse should administer 2.8 mL of the pentamidine solution.

Explanation

1. Conversion of Weight:
   Converting the client’s weight to kilograms ensures that the dosage calculation is accurate according to the weight-based dosing guideline. Weight conversion is essential because medical dosages are typically calculated in metric units.
2. Calculating Dosage:
   By multiplying the weight in kilograms by the dosage per kilogram, you get the total amount of drug needed in milligrams. This step is crucial for determining the precise amount of medication required for safe and effective treatment.
3. Volume Calculation:
   Knowing the concentration of the solution allows you to convert the total dose in milligrams into the volume of solution needed. This step ensures that the correct amount of medication is drawn from the vial, minimizing dosing errors.

Rounding the final volume to the nearest tenth (2.8 mL) is standard practice to ensure precision without overcomplicating measurements.