Drawing up

[tony.quinn]

order is .5mg, stock is 5 mg in 1 ml. how much do i draw up? how should i look at tis?

[Esme12, ASN, BSN, RN]

DosageHelp.com - Helping Nursing Students Learn Dosage Calculations - Mass for Mass Questions

[TABLE=class: example]

[TR]

[TD][TABLE=class: fraction]

[TR]

[TD=class: numerator]Ordered

[/TD]

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[TR]

[TD=class: denominator] Have [/TD]

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[/TD]

[TD] x Volume Per Have

[/TD]

[TD] = Y (Liquid Required) [/TD]

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[/TABLE]

[KelRN215, BSN, RN]

Desired/on hand.

Your ordered dose is 0.5 mg. On hand, you have 5 mg in 1 mL. 0.5mg/5 mg/mL = X mL. The mg cancel each other out and you solve for X mL.

[Daisy_08, BSN, RN]

FYI - make sure you always add the 0 in front of any decimal place!

[anneuhbanana]

Sometimes it's easier to look at it without formulas. I say how many ml are in each mg. So 0.2ml in 1mg and you need 0.5mg so how many ml is that?

[ADN2B]

0.5mg x 1mL/5mg = mL

[BloomNurseRN, ASN, BSN, RN]

I'm definitely a fan of equations in these examples. We do "desired"/"have" x quantity. We shorten it to D/H x Q.

For your example it would be 0.5 mg/5 mg x 1 ml. This then multiples out to 0.5 ml.

You always have to be careful that you have the same measurements (i.e. mg, mcg, etc) but otherwise this is a quick, easy way to work out this type of problem.

[Anoetos, BSN, RN]

The formula is (O / OH)V = x where O is ordered amount (mass), OH is on hand amount (mass) and V is on hand volume.

Order is for 0.5mg

On hand qty is 5mg/mL in 1 mL

So: (0.5mg/5mg)1mL = 0.1mL (the masses cancel, besides you know you're looking for volume)

Draw it up in a little tiny syringe...

Also, you know that the desired amount is exactly one tenth the available full amount in 1mL...so, one tenth of a mL...

Honestly, I rarely do the math. Once you're used to it, most of the time you just "see it".