Med Math Help

Nursing Students General Students

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Please help with this problem

The patient is ordered levofloxacin 750 mg in 150 ml of d5w to infuse over 90 minutes. The client weighs 150lbs. Calculate the dosage in ml/hr.

Specializes in Pharmacy, Mathematics, Physics, and Educator.

The only thing that matters is the 150 mL over 90 minutes. See if you can change that to mL/h.

Specializes in Psychiatry.

(150/90) x (60/1)

Rate is ml/hour

1 hour is 60 minutes. In this example you have 90 minutes and not 60. 150 (rate) / 90 (time)

To get your answer in an hour, multiply by 60.

Specializes in Pharmacy, Mathematics, Physics, and Educator.

So just to be technically clear, you are starting with 150 mL/90 min and have to end up with mL/h. You will multiply by 60 min/h. Min will cancel out leaving 100 mL/h.

Specializes in Pharmacy, Mathematics, Physics, and Educator.

You might want to check out this article. You can also download my dosage calculation book there.

https://allnurses.com/pre-nursing-student/master-your-drug-1148937.html

Specializes in SRNA.

Always read what the question is asking you to solve for. Skip the beginning so you don't confuse yourself with the distractors.

For this example, you are solving for mL per hour or mL/hr. Now read the entire question.

Now set up the equation in the order of what you are solving for (mL on top hr on bottom) with this being the first part of your equation.

So: 150mL OVER 90 minutes (150mL/90 mins)...get rid of mins and convert to hr.

150mL/90 mins x 60 mins/hr = 150 ml/90 x 60/hr = 9000 mL/90hr = 100 mL/hr

Specializes in 15 years in ICU, 22 years in PACU.
Always read what the question is asking you to solve for. Skip the beginning so you don't confuse yourself with the distractors.

For this example, you are solving for mL per hour or mL/hr. Now read the entire question.

Now set up the equation in the order of what you are solving for (mL on top hr on bottom) with this being the first part of your equation.

So: 150mL OVER 90 minutes (150mL/90 mins)...get rid of mins and convert to hr.

150mL/90 mins x 60 mins/hr = 150 ml/90 x 60/hr = 9000 mL/90hr = 100 mL/hr

It's usually most helpful to ask what the student already knows. How have they tried to solve the problem rather than just to solve it for them.

Thanks so much everyone for your help! I was distracted by the 750 mg. I kept trying to fit it into the calculation

It's usually most helpful to ask what the student already knows. How have they tried to solve the problem rather than just to solve it for them.

I agree. I really think it should be a TOS violation to just give someone the answer to a question.

This is a pretty good example of how "help" should go:

https://allnurses.com/general-nursing-student/i-cant-figure-1168609.html

Giving them the answer but walking them through how it's done is a good way to teach them how to do it though. Then knowing the answer, they can always go back and see if they're doing it right because they know what the answer should be.

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