Chapter 11 Parenteral Dosage of Drugs by e788dz6

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									Parenteral Dosage of Drugs
        Chapter 11
Calculation of Drug Dosage:
         Parenteral




                              2
     Calculation of Drug Dosage:
              Parenteral
• Order
  – Cleocin 150 mg IM every 12 hours
• Available
  – Cleocin (clindamycin phosphate) 300 mg per
    2 mL



                                                 3
    Calculation of Drug Dosage:
             Parenteral
• Step 1. Convert
  – No conversion is necessary.




                                  4
    Calculation of Drug Dosage:
             Parenteral
• Step 2. Think
  – You want to give less than 2 mL
                                                  1
  – Actually, you want to give 150 mg, which is   2
                   1
    of 300 mg and 2 of 2 mL, or 1 mL
  – Calculate to double-check your estimate.



                                                      5
    Calculation of Drug Dosage:
             Parenteral
• Step 3. Calculate
             300 mg 150 mg
                    
              2 mL      X
              300 X  300
                 X  1 mL


                                  6
    Calculation of Drug Dosage:
             Parenteral
• Given intramuscularly every 12 hours
• Select a 3 mL syringe
• Measure 1 mL of Cleocin 300 mg per 2 mL




                                         7
       Ratio-Proportion Method:
      Parenteral with Conversion

• Order: Robinul 150 mcg IM
  stat
• Supply: Robinul 0.2 mg per
  mL




                                   8
      Ratio-Proportion Method:
     Parenteral with Conversion
• Step 1. Convert
  – Equivalent: 1 mg = 1,000 mcg
             1,000 mcg      X
                       
                1 mg     0.2 mg
                    X  200 mcg

                                   9
      Ratio-Proportion Method:
     Parenteral with Conversion
• Step 2. Think
  – Give less than 1 mL but more than 0.5 mL
    • Don’t be fooled into thinking 0.2 mg is less than
      150 mcg
    • 0.2 mg is more than 150 mcg
    • 0.2 mg = 200 mcg


                                                          10
      Ratio-Proportion Method:
     Parenteral with Conversion
• Step 3. Calculate
            200 mcg 150 mcg
                   
             1 mL        X
                    200 X
                     150
                 X  0.75 mL


                                  11
       Ratio-Proportion Method:
      Parenteral with Conversion
• Given intramuscularly immediately
•   Select a 1 mL syringe
•   Measure 0.75 mL Robinul 0.2 mg per mL
•   You may have to change needles, as this
    is an IM injection.
                                          12
Guidelines for Syringe Selection
• Standard doses more than 1 mL
  – Round to tenths and measure in a 3 mL
    syringe
  – 3 mL syringe is calibrated to 0.1 mL
    increments
    • 1.53 mL is rounded to 1.5 mL
    • Drawn up in a 3 mL syringe


                                            13
Guidelines for Syringe Selection
• Small (less than 1 mL), critical care, or
  children’s doses
  – Round to hundredths and measure in 1 mL
    syringe
  – 1mL syringe is calibrated in 0.01 increments
     • 0.257 mL is rounded to 0.26 mL
     • Drawn up in a 1 mL syringe


                                                   14
Guidelines for Syringe Selection
• Amounts of 0.5 –1 mL calculated in tenths
  • Can be accurately measured in either a 1 mL
    or 3 mL syringe




                                                  15
                  Insulin Label
 Concentration           Manufacturer
                                                  Brand Name   Storage




                                        Species
                  Type
                         Generic Name
Expiration Date
                                                                    16
Combination Insulin Dosage



  40 units    12 units
      NPH     Regular
 Units-100    Units -100 insulin
    insulin

      Total insulin dosage = 52 units   17
Preparing Combination Insulin Dosage

  1. Inject       2. Inject
     30 units         10 units
     of air.          of air.




                                 18
Preparing Combination Insulin Dosage

 3. Withdraw     4. Withdraw
    10 units        30 units
    regular.        NPH for a
                    total of 40
                    units.




                                  19
          Insulin Sliding Scale
• Order
  – Humulin R Regular units-100 insulin subcut
    based on glucose reading at 1600




                                                 20
            Insulin Sliding Scale
       Insulin Dose       Glucose Reading*
        No coverage       Glucose less than 160
           2 units               160–220
           4 units               221–280
           6 units               281–340
           8 units               341–400
*   Glucose is greater than 400: Hold insulin; call MD stat.

                                                               21

								
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