# PO Dose Calculator: Liquid Form

## Dose Formula: Liquids

$\frac{O×V}{A}$
• O = Dose ordered
• V = Volume of dose available
• A = Dose available
It doesn't matter what type of units are used in this formula.  You can figure out how many grams to give or how many milligrams to give, micrograms, units, grains, etc.  Remember to be consistent in basic mode (e.g., don't mix milligrams with grams).

## Examples

1. Give 100 milligrams (mg) of theophylline elixir.  The elixir comes as 27 mg per 5 milliliters (mL).  Using the formula, a dose of 18.5 mL is prepared.  In this example:

• Dose ordered = 100 mg
• Volume of dose available = 5 mL
• Dose available = 27 mg
$\frac{\mathrm{100 mg}×\mathrm{5 mL}}{\mathrm{27 mg}}$

The answer is = 18.5 mL

2. Another example, give 650 mg of liquid Tylenol® (acetaminophen). The liquid Tylenol® comes in a concentration of 120 mg per 5 mL. How much medication would you give? Answer: 27 mL.

• Dose ordered = 650 mg
• Volume of dose available = 5 mL
• Dose available = 120 mg
$\frac{\mathrm{650 mg}×\mathrm{5 mL}}{\mathrm{120 mg}}$

The answer is = 27.08 mL.