Dosage Calculations for Nursing Students | Step-by-Step Practice Problem

13 Jun 2025 · 1 min

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In this instructional segment, the instructor walks nursing students through a step‑by‑step dose‑calculation problem involving ondansetron. The patient’s order is for 8 mg to be given three times daily after surgery, and the medication is stocked as 4 mg tablets. The instructor emphasizes the first step of any dose‑calculation: identify the desired final unit (tablets). Next, the physician’s order (8 mg) is written on the left side of a conversion chart, and the available dosage form (4 mg per tablet) is placed on the right. The third step is to determine the conversion factor (1 tablet = 4 mg). By arranging the values in a proportion, the calculation 8 mg × 1 tablet / 4 mg yields 2 tablets, which is the correct answer. The narration reinforces the systematic approach—goal, order, conversion—ensuring students can reliably translate milligram orders into tablet counts.

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Let's walk through a dose calc practice question. Mr. Rothi is scheduled for surgery this afternoon. He's asking about his medications after surgery and asking about ondansetron. His order states that he can have 8mg TID following the surgery. And you know that the med cart has four milligram tablets. You explained to Mr. Rothi that he can take how many four milligram tablets after surgery. So anytime we answer a dose cop question, we're always going to walk through our steps. And the first step, always, always, my friend, is what you need at the end. So what units do we need to end up with at the end? And this question here is asking us for tablets, how many of those 4 milligram tablets can you have after surgery? So we're going to start with tablets here and write this. Our next step is what is the order? So this is what we need to end up with at the end.
Our.
Our next step is what is the order? What did the doctor actually order? And here, the doctor ordered 8 milligrams of that medication, ondansetron. So the order goes on the left side. The need, what we need to end up with goes on the right. And now the third step is what conversions, what conversions do we need to get from 8 milligrams here to tablets? And the question itself tells us. So what we have in the med cart is we have four 4 milligram tablets. So each tablet, one tablet is 4 milligrams. So we need one tablet is 4 milligrams. Now we're here with 8 milligrams and down here with 4 milligrams milligrams crosses out, we are left only with tablets, which is exactly what we want. So now we can multiply across the top, multiply across the bottom, and divide those two numbers. So 8 times 1 is 8. 4 times 1 really is 4, and 8 divided by 4 gives us two tablets.