The recommended children’s dosage of Keflex is 25 to 50 mg/kg/day in divided doses. The maximum daily safe dosage for a child weighing 42 lb is: Round to the nearest tenth.
The correct answer and Explanation is :
To determine the maximum daily safe dosage of Keflex (cephalexin) for a child weighing 42 lb, follow these steps:
Step 1: Convert the child’s weight from pounds to kilograms.
1 pound is approximately 0.453592 kilograms.
[ \text{Weight in kg} = 42 \text{ lb} \times 0.453592 \text{ kg/lb} ]
[ \text{Weight in kg} = 19.05 \text{ kg} ]
Step 2: Calculate the maximum daily dosage based on the recommended dosage range.
The recommended dosage is 25 to 50 mg/kg/day. To find the maximum dosage:
[ \text{Maximum daily dosage} = 50 \text{ mg/kg/day} \times 19.05 \text{ kg} ]
[ \text{Maximum daily dosage} = 952.5 \text{ mg/day} ]
Step 3: Round the result to the nearest tenth.
The maximum daily safe dosage of Keflex for a child weighing 42 lb is 952.5 mg/day, rounded to the nearest tenth.
Explanation
Keflex, a cephalosporin antibiotic, is prescribed based on body weight to ensure the child receives an effective but safe amount of medication. Pediatric dosages often vary based on the child’s weight and the specific condition being treated. In this case, the range of 25 to 50 mg/kg/day ensures flexibility depending on the severity of the infection and the child’s tolerance.
By converting the child’s weight from pounds to kilograms, we align with the metric-based dosage recommendations. The conversion factor (0.453592) is used because medical dosages are generally calculated in kilograms. Calculating the maximum safe dosage helps prevent potential overdose and side effects while providing enough medication to effectively treat the infection. Always consider that dosages should be personalized by a healthcare professional, and this calculation serves as a general guide based on provided standards.