Medical Math

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Medical Math

• Operations and Formulas

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Metric Abbreviations for Weight
Kilogram kg Gram gm Milligram mg Microgram mcg M
etric Equivalencies for Weight 1 kilogram 1000
g 1gram 1000 mg 1 milligram 1000 mcg
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• Household Abbreviation /
  Metric / Apothecary
• 1 cup C
  240 cc
• 1 tablespoon T (tbs)
  15 cc or 15 ml
• 1 teaspoon t (tsp)  
  5 cc
• drop gtt
  depends on
  size of the drop
• pound lb
  2.2 lb 1 kg 1 lb. 16 oz

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• The formula method
• D x Q X
• H
• D - dosage desired or orderedH - what is on hand
  (available)Q - unit of measure that contains the
  available dose. When using solid products
  (tablets, capsules) Q is always 1 and can be
  eliminated. Q varies when using liquid
  measures.X - the unknown dosage you need to
  administer

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Units

• Calculating dosages in units (insulin, heparin,
  pitocin, vitamins, some antibiotics)
• Example  Ordered   Heparin 8000 units
  subcutaneous q12h          Available   Heparin
  10,000 units per ml                   How much
  will you administer?
•   Formula   8000 units   X 1 ml 0.8 ml
                       10,000 units

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Calculations based on body weight

• The first step is to convert the patients body
  weight into kg. The formula is 2.2 lb. 1 kg.
• The second step is to  calculate the medication
  dose.
•   a.  Calculate the daily dose
•   b.  Divide the daily dose by the number of
  doses to be administered.
•   c.  Use either the ratio-proportion or formula
         method to calculate the number of
  tablets/capsules or volume to be administered
  with each dose

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Temperature Conversion
C (F-32) 5/9 or 0.5556 F (C) 9/5 or 1.8
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