The daily dose of antibiotic for the treatment of an ear infection is 115 mg/kg of body weight. If the antibiotic tablets are available in 250 mg size, calculate the number of tablets that a 33.5 lb. child must take per day
The correct answer and explanation is :
To solve this problem, we need to follow several steps involving unit conversion, dosage calculation, and tablet counting.
Step-by-Step Solution:
Step 1: Convert the child’s weight from pounds to kilograms (kg)
We are given:
- Weight = 33.5 lb
- Conversion factor: 1 kg = 2.2 lb
[
\text{Weight in kg} = \frac{33.5}{2.2} \approx 15.23\ \text{kg}
]
Step 2: Calculate the total daily antibiotic dose
The prescription is:
- 115 mg per kg of body weight per day
[
\text{Total daily dose} = 115\ \text{mg/kg} \times 15.23\ \text{kg} \approx 1751.45\ \text{mg/day}
]
Step 3: Determine how many 250 mg tablets are needed
Available tablet strength = 250 mg/tablet
[
\text{Number of tablets} = \frac{1751.45}{250} \approx 7.01
]
So, the child needs to take approximately 7 tablets per day.
Since partial tablets may not be recommended depending on the formulation (especially for coated or extended-release tablets), a clinician or pharmacist would need to confirm the exact dosing method. However, for this problem:
✅ Final Answer: 7 tablets per day
300-Word Explanation:
This problem involves a typical pediatric medication calculation that requires careful conversion and application of dosage principles. The dosage for many medications is based on body weight, especially in children, to ensure safety and efficacy. Here, the child weighs 33.5 pounds, which needs to be converted into kilograms because medical dosing is typically done using the metric system (milligrams per kilogram). Dividing 33.5 lb by 2.2 gives us approximately 15.23 kg.
Next, the total dose is calculated using the prescribed dosage of 115 mg per kg. Multiplying 115 mg/kg by 15.23 kg results in approximately 1751.45 mg per day. This is the total amount of antibiotic the child needs to receive each day.
The final step is to determine how many tablets this equates to, given that each tablet contains 250 mg of the antibiotic. Dividing 1751.45 mg by 250 mg/tablet gives us approximately 7.01 tablets. Since tablets usually come in fixed sizes, and it may not be safe or practical to split them (especially if they are not scored or are extended-release), most clinicians would round to the nearest whole number—in this case, 7 tablets per day.
This calculation emphasizes the importance of accuracy in pediatric dosing, as underdosing may lead to ineffective treatment and overdosing can cause toxicity. Always confirm with a healthcare provider before adjusting doses based on weight.