SHEET (FOUNDATIONS)
AT CHAMBERLAIN
NR293 – Pharmacology
CALCULATION CHEAT SHEET (QUIZ 1)
1. Basic Measurement Conversions (MEMORIZE)
Metric Conversions
1 g = 1000 mg
1 mg = 1000 mcg
1 L = 1000 mL
Move decimal 3 places:
g → mg → mcg (right)
mcg → mg → g (left)
2. Basic Dosage Formula (MOST TESTED)
Formula
Dose to Give=Ordered DoseAvailable Dose×Quantity\textbf{Dose to Give} = \frac{\text{Ordered Dose}}{\
text{Available Dose}} \times \text{Quantity}Dose to Give=Available DoseOrdered Dose×Quantity
Example
Order: 250 mg
Available: 500 mg per tablet
, 250500×1=0.5 tablet\frac{250}{500} \times 1 = 0.5 \text{ tablet}500250×1=0.5 tablet
3. Liquid Medication Calculations
Formula
Ordered DoseDose on Hand×mL\frac{\text{Ordered Dose}}{\text{Dose on Hand}} \times \
text{mL}Dose on HandOrdered Dose×mL
Example
Order: 125 mg
Available: 250 mg / 5 mL
125250×5=2.5 mL\frac{125}{250} \times 5 = 2.5 \text{ mL}250125×5=2.5 mL
4. Weight-Based Dosing (INTRO LEVEL)
Key Rule
Convert kg → lb if needed
o 1 kg = 2.2 lb
Example
Patient weight: 154 lb
154÷2.2=70 kg154 \div 2.2 = 70 \text{ kg}154÷2.2=70 kg
If order is mg/kg, multiply:
70×ordered mg70 \times \text{ordered mg}70×ordered mg
5. Safe Dose Range (FOUNDATION CONCEPT)
Steps
1. Calculate minimum safe dose
2. Calculate maximum safe dose
3. Check if ordered dose falls within range
If ordered dose is outside range → HOLD & notify provider