PLEASE HELP! Diluent problems!

  1. Hi everyone. I'm new here and hoping for some help! I am a new RN and am getting ready to start my first job. We received a study guide for a test we will have to take IN THREE DAYS and I HAVE NO IDEA how to do some of these problems. I am so stressed out already. PLEASE HELP!

    1. The physician has ordered potassium penicillin G 125,000 units by injection for your patient. You have availablea vial of powdered potassium penicillin G labeled 1,000,000 units. Please solve one of the dilutions using the label below.

    Preparation of solution:
    Diluent added Final Concentration
    9.6 ml 100,000 units/ml
    4.6 ml 200,000 units/ml
    3.6 ml 250,000 units/ml

    I only need to know how to do one, but I don't know how to do ANY!

    2. Ampicillin 1.5gm is ordered every 4 hours. You add 6.8 mL sterile H20 as a diluent to the 2 gm vial creating a solution concentration of 250 mg/ml. How many mls are needed for a 1.5 gm dose?

    3. The physician has ordered potassium penicillin 3,000,000 units by injection for your patient. You have available a vial of powdered potassium penicillin G labeled 5,000,000 units.

    Preparation of solution:
    Add diluent: Total concentration

    23 ml 200,000 units/ml
    18 ml 250,000 units/ml
    8 ml 500,000 units/ml
    3 ml 1,000,000 units/ml

    I only have to choose one diluent and one concentration, but I don't know WHAT to do!

    ANY HELP IS SO APPRECIATED! I feel so dumb and unprepared!!
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    Joined: Dec '10; Posts: 1


  3. by   WSU_Ally_RN
    For all of these, remember your equation

    (Ordered Dose/What you have)XmL

    So for the first question, if you chose to use the 9.6mL dilutent, the equation would look like this:

    (125,000 units/100,000 units)X9.6 mL

    I use that equation often... its a good one to know. Good luck!
  4. by   Jonathank
    Old post on a dead board, but just for giggles:

    1. I'd go with the bottom dilution to avoid having to give multiple shots. If 3.6 mL has 250K units and 125K units are ordered, give 1.8 mL.

    2. 250 mg/mL = 0.25 g/mL = 1.5 g/6 mL Give 6 mL.

    3. Use the bottom dilution again for the same reason as in #1.

    1M units/mL = 3M units/3 mL. Give 3 mL.