hello "i need some help"

  1. Im taking Pharmacology and we are in some converstions and im a little lost i was wondering if some one could help the problem reads

    Order: Phenobarbital gr 1/6 p.o t.i.d

    Supply: phenobarbital elixir 20mg per 5 ml

    Give: _____________ ml


    im not sure how to put it in the converstion
    i know that gr1/6 is 10mg

    but a little lost from there (i think im just over thinking it) but if you could help i would be so greatful !:uhoh21:
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  2. 3 Comments

  3. by   truern
    Dang, girl!! You did the hard part

    Okay, if there are 20 mg in 5 mL, and you want to give 10 mg, set it up:

    20 mg/5 mL = 10 mg/X mL (I hope you know these are over each other..I can't get it to print right)

    Cross multiply to get 20X=50...Divide 20X by 20 to get the X by itself. Whatever you do to one side of the equation, you have to do to the other, so divide 50 by 20, too. X=50/20 or 2.5 mL

    Was that clear as mud??
  4. by   redaries
    i guess i dont understand how to get the 20x=50 that is where im confused i guess

    Quote from truesn
    Dang, girl!! You did the hard part

    Okay, if there are 20 mg in 5 mL, and you want to give 10 mg, set it up:

    20 mg/5 mL = 10 mg/X mL (I hope you know these are over each other..I can't get it to print right)

    Cross multiply to get 20X=50...Divide 20X by 20 to get the X by itself. Whatever you do to one side of the equation, you have to do to the other, so divide 50 by 20, too. X=50/20 or 2.5 mL

    Was that clear as mud??
  5. by   redaries
    Lets see if my brain is working right 10mg/20mg X 5ml= 2.5 ml


    Quote from redaries
    i guess i dont understand how to get the 20x=50 that is where im confused i guess

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