Medication - Metric Conversions


Metric units and conversions for the calculation and administration of medication.


Basic Metric Units for drug administration



Quantity
Unit
Symbol
length
metre
m
mass
gram
g
volume
litre
l
time
second
s


Common Units of Measurement for drug administration

The various quantities of these units often have a prefix to make writing quantities more succinct. For example 0.000001g may be written as 1 mcg (or 1µg.)

Prefix

Symbol

Multiplication factor

mega
M
1,000,000
kilo
k
1,000
hecto
h
100
deka
da
10
unit
e.g. g, m, l or s
1
deci
d
0.1
centi
c
0.01
milli
m
0.001
micro
mcg or µ
0.000001



Converting a number from one metric unit to another involves moving the decimal place to the left or the right. To work out how many decimal places to move:
  1. Identify the metric scale
  2. Identify the two units in the problem
  3. Count the number of units from the current unit to the desired unit
  4. Move the decimal point the number of places from the given unit to the desired unit

Example 1 - Convert 0.1 grams to milligrams.
The decimal point is moved 3 places to the right - 0.1 g = 100 mg

Example 2 - Convert 375 millilitres to litres.
The decimal point is moved 3 places to the left - 375 ml = 0.375 l





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