Dosage calculation Help!

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Hi! Im in my 3rd semester of my ADN program and we just started advanced dosage calculations and i came across some problems that i have no idea how to do. Here it is:

Drug A 10mg ordered. The pharmacy sends up drug A 5mg/2mL. The drug reference states to dilute to a concentration of 1mg/mL and administer at a rate of 5mg per minute.

  • The total volume the nurse will administer is______mL
  • The nurse will add____mL of dilutent to make the appropriate concentration of the drug.
  • Over how many minutes will the medication be administered over?

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Why don't you show us what you'very done so far?

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Well this is like the first one. I'm jumping ahead of the class because im so terrible at math and literally have no idea where to start. I searched the Internet for sample problems like this and couldn't find any.

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Specializes in ICU, LTACH, Internal Medicine.

You got 5 mg/2 ml. You need 10 mg, therefore you need 2 such doses (10/5=2), so you need 4 ml.

1 mg/1 ml = > 10 mg/10 ml. You already got 4 ml, so you add 10 - 4 =6 ml of diluent

You got 1 mg/ml. Your 1 min rate is 5 mg, or 5 ml. So, 1 min to shoot 5 ml, 2 min to shoot it all (10/5 = 2).

Disclaimer: you may be taught to do the same with some exotic looking proportions and equations. You may still have to study them but on NCLEX nobody cares how you get result as long as it is correct. So just follow simple logic :)

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You are ordered to administer 10 mg of drug a, which is available 5mg/2 mL. To determine the volume you can use the following formula: (D÷ H) × V. D = the ordered dose (10 mg), H = the available formulation (5 mg), and V = the volume (2 mL) for H (5 mg).

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Wow thank you!

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There was one more if you could take a look at it.

150mg IVP ordered. Available is drug B 50mg/mL. The drug reference says to dilute with 4.5mL NS.

The nurse will have____ mL of medication to draw up after dilution.

What is the concentration of the solution after dilution?

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Specializes in Med/Surg, Ortho, ASC.
There was one more if you could take a look at it.

IVP ordered. Available is drug B 50mg/mL. The drug reference says to dilute with 4.5mL NS.

The nurse will have____ mL of medication to draw up after dilution.

What is the concentration of the solution after dilution?

It is not at all helpful if folks continue to feed you answers. You simply will not learn that way. These folks will not be there to take your dosage calculation tests (passage of which is a non-negotiable fact of nursing school, not to mention patient safety).

That is an extremely simple arithmetic question. If you are not able to think it through, you need to approach your instructor or an advisor to help get you into some sort of remedial tutoring or basic arithmetic class to get you up to speed.

Good luck.

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Specializes in ICU, LTACH, Internal Medicine.
There was one more if you could take a look at it.

150mg IVP ordered. Available is drug B 50mg/mL. The drug reference says to dilute with 4.5mL NS.

The nurse will have____ mL of medication to draw up after dilution.

What is the concentration of the solution after dilution?

150mg /50 mg =3. 1 ml - 50 mg =>> 3 ml - 150 mg

3 ml + 4.5 ml = 7.5 ml, which still contain those 150 mg of drug

150mg /7.5ml = 20 mg/ml

P.S. is that what's named "advanced" drug calculations nowadays??

What are you going to do with a guy who came from another hospital with forgotten IV hanging there infusing vanco 1 g in 250 ml of NS 167 cc/h, part of it already in; you disconnect the IV but, very luckily, in your turn forgot to throw it away, because in 10 min pharm is calling and asking you how much exacly of vanco the patient got already and when approximately the infusion was started. They need the numbers to recalculate the dose.

Patient came in 1430, volume 250, dose 1 g/250 ml, rate 167 cc/h, 125 cc exactly left in bag, pharm wants to know how much to add to total dose of 2 g (accounting for the dose the patient already got) Try to do this, show your work.

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Specializes in Med/Surg, Ortho, ASC.
150mg /50 mg =3. 1 ml - 50 mg =>> 3 ml - 150 mg

3 ml + 4.5 ml = 7.5 ml, which still contain those 150 mg of drug

150mg /7.5ml = 20 mg/ml

P.S. is that what's named "advanced" drug calculations nowadays??

What are you going to do with a guy who came from another hospital with forgotten IV hanging there infusing vanco 1 g in 250 ml of NS 167 cc/h, part of it already in; you disconnect the IV but, very luckily, in your turn forgot to throw it away, because in 10 min pharm is calling and asking you how much exacly of vanco the patient got already and when approximately the infusion was started. They need the numbers to recalculate the dose.

Patient came in 1430, volume 250, dose 1 g/250 ml, rate 167 cc/h, 125 cc exactly left in bag, pharm wants to know how much to add to total dose of 2 g (accounting for the dose the patient already got) Try to do this, show your work.

NM. I wish folks would stop feeding answers to OP and require her to get some consistent tutoring.

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Well that was kind of rude...

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150mg /50 mg =3. 1 ml - 50 mg =>> 3 ml - 150 mg

3 ml + 4.5 ml = 7.5 ml, which still contain those 150 mg of drug

150mg /7.5ml = 20 mg/ml

P.S. is that what's named "advanced" drug calculations nowadays??

What are you going to do with a guy who came from another hospital with forgotten IV hanging there infusing vanco 1 g in 250 ml of NS 167 cc/h, part of it already in; you disconnect the IV but, very luckily, in your turn forgot to throw it away, because in 10 min pharm is calling and asking you how much exacly of vanco the patient got already and when approximately the infusion was started. They need the numbers to recalculate the dose.

Patient came in 1430, volume 250, dose 1 g/250 ml, rate 167 cc/h, 125 cc exactly left in bag, pharm wants to know how much to add to total dose of 2 g (accounting for the dose the patient already got) Try to do this, show your work.

Not sure if you understand. I'm on the 3rd semester of an ADN program. We haven't learned much of these things just yet. I'm jumping ahead of my class to get a head start because I'm terrible at math.

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