EXAMPLE 2. Express 2200 ml as liters.
2200 ml = X L
1000X = 2200
X = 2.2 L
(b) To change liters to milliliters, kilograms to grams, grams to
milligrams, set up a ratio and proportion based on the equivalent.
Express 3.5 liters as ml.
3.5 L = X ml
X = 3500 ml
Express 0.5 gm as mg.
0.5 gm = X mg
1 gm = 0.5 gm
X = 500 mg
b. The Apothecaries' System.
(1) The apothecary system is the original system of medication
measurement used by pharmacists and physicians. The system is still in use today to a
limited extent. In general, drugs that continue to be ordered and dispensed in
apothecary units are those that have been in use for many years. For most other drugs
the metric system is the system of measurement commonly used.
Apothecary equivalents to the metric system.
1 ounce (oz) = 30 ml
8 oz = 240 ml (approximate)
1 quart (qt) = 1000 ml (approximate) (4 cups)