Question

A child weighing 12 kg is to receive ampicillin in the recommended dosage of 75 mg per kg daily. The ampicillin is available as an oral solution labeled 250 mg/5 mL. How many mL of the solution will the patient receive daily?

Answer 1

Conversions

In order to find the daily number of mL of the solution, we first will find the number of mg, secondly we convert that quatity into mL.

Step 1: number of mg per day

Since the recommended dosage is 75 mg per kg daily, and the child weighs 12 kg, then the dosage for that child is

75 mg/kg x 12kg = 900 mg

Then, the recommended dosage is 900 mg

Step 2: number of mL per day

Now, we are going to find the number of mL based on the number of the mg dosage.

We want to find the number of mL that the child is going to receive if we receives 900 mg.

We know that he would receive 5 mL is the dosage is 250 mg. Then we have the following relationship:

900 mg ⇔ ?? mL

250 mg ⇔ 5 mL

If we divide both sides we would have the same result:

`\begin{gathered} (900)/(250)=(??)/(5) \\ \downarrow \\ (900)/(250)\cdot5=?? \\ \downarrow \\ 3.6\cdot5=18=\text{??} \end{gathered}`

Then,

900 mg ⇔ 18 mL

250 mg ⇔ 5 mL

Therefore, for a dosage of 900 mg, he would receive 18 mL

Answer: 18 mL