A client who weighs 154 pounds receives a prescription for levothyroxine 1.6 mcg/kg by mouth (PO) daily. The medication is available in 112 mcg scored tablets. How many tablets should the nurse administer? (Enter numerical value only.)
The correct answer and Explanation is :
To determine how many tablets of levothyroxine the nurse should administer, we first need to calculate the appropriate dose in micrograms (mcg) based on the client’s weight and the prescribed dosage.
- Calculate the client’s weight in kilograms (kg):
- Weight in pounds = 154 lb
- Conversion factor: 1 kg = 2.2 lb
[
\text{Weight in kg} = \frac{154 \text{ lb}}{2.2 \text{ lb/kg}} \approx 70 \text{ kg}
]
- Calculate the prescribed dose in mcg:
- Dosage = 1.6 mcg/kg
[
\text{Total dose} = 1.6 \text{ mcg/kg} \times 70 \text{ kg} = 112 \text{ mcg}
]
- Determine how many tablets to administer:
- Each tablet contains 112 mcg.
[
\text{Number of tablets} = \frac{\text{Total dose}}{\text{Dose per tablet}} = \frac{112 \text{ mcg}}{112 \text{ mcg/tablet}} = 1 \text{ tablet}
]
Thus, the nurse should administer 1 tablet of levothyroxine.
Explanation:
Levothyroxine is a synthetic form of the thyroid hormone thyroxine (T4), used primarily to treat hypothyroidism. The dosing of levothyroxine is often based on the patient’s weight to ensure that the amount administered is appropriate for their metabolic needs. In this scenario, the prescription was given in mcg/kg, which requires converting the patient’s weight from pounds to kilograms for accurate calculation.
After determining the patient’s weight in kg, the total daily dose is calculated by multiplying the weight by the prescribed mcg/kg. This ensures that the patient receives an adequate amount of the hormone to restore normal thyroid function.
Since the available formulation of levothyroxine is in 112 mcg scored tablets, it is essential to confirm that the calculated total dose matches the tablet’s strength. In this case, administering one tablet delivers exactly the prescribed amount. Careful calculations and considerations are vital in medication administration to avoid underdosing or overdosing, especially with medications that have a narrow therapeutic index like levothyroxine.