Calculation help..

  1. 0
    Here's the problem:
    Ordered: Morphine Sulfate 5 mg
    Available: Morphine Sulfate gr.1/6 per mL.

    Normally, I convert the fraction to a decimal because I don't like working with fractions, but this problem isn't working out for me either way. Can anyone help me figure this one? The answer key says 0.5 mL
  2. 5 Comments so far...

  3. 1
    Are you forgetting to convert the grains to mg? 1grain=64.79891 mg
    Esme12 likes this.
  4. 0
    That is correct. I convert the gr to mg. So I say there is 60mg/1gr so there are Xmg/.17gr (6/1=.166). That gives you 10 mg. Then do D/H*V. So 5/10*1=.5. Hope that helped. I am so bad at math but for some reason calculation clicked with me. Good Luck!
  5. 0
    Nursing Math - Medical Dosage Equations Formulas Calculators Examples Solutions For Nurses
    http://www.davesems.com/files/drug_d...lculations.pdf
    DosageHelp.com - Helping Nursing Students Learn Dosage Calculations

    Medical Metric Conversion Tables and Dose Data
    1 pound (avoirdupois) = 453.592 g 1/2 grain = 30 mg
    1 pound (apothecary) = 373.242 g 1/4 grain = 15 mg
    1 ounce (avoirdupois) = 28.35 g 1/8 grain = 8 mg
    1 ounce (apothecary) = 31.10 g 1/12 grain = 5 mg
    15 grains = 1 g 1/100 grain = 600 mcg
    10 grains = 600 mg 1/150 grain = 400 mcg
    7 1/2 grains = 500 mg 1/200 grain = 300 mcg
    5 grains = 300 mg 1/250 grain = 250 mcg
    1 1/2 grains = 100 mg 1/300 grain = 200 mcg
    1 grain = 64.79891 mg 1 kilogram = 2.2 pounds
    1 pound = 0.45 kilograms (kg) 1 stone = 6.35 kg
    1000 mcg = 300 to 7000 iu (below) 1000 mcg = 1 mg
    1 scruple = 1.2 g 1 drachm = 28.8 g
  6. 0
    There are roughly 60mg in 1 grain. 1/6th of 1 grain would be 1/6th of 60mg 1/6 of 60 is 10. therefore, the concentration is 10mg/ml. For 5mg, you need half of that 10mg in 1ml, or 0.5ml.

    <rant> And when are these nursing schools going to realize that no one uses grain, drams, minims, or avoirdupois ounces any more? </rant>
  7. 0
    Thank you so much!! That helped tremendously! I glide right through these calculations until they trip me up with that stupid apothecary system. I'm so glad it's not used much!


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