Overview
This lecture covers the Avoirdupois and Household measurement systems, their importance in pharmacy, and how to convert between these and the Metric system.
Measurement Systems in Pharmacy
- The Avoirdupois and Household systems use pounds (lb), ounces (oz), and fluid ounces (fl oz) for weight and volume.
- The Household system includes teaspoons (tsp), tablespoons (tbsp), cups, and pints, commonly used in daily life.
- The Avoirdupois system is essential for accurately measuring bulk drugs in pharmacies.
- The Household system is convenient but less accurate due to variable measuring tools.
- The Metric system is the scientific standard, providing precise and consistent measurements.
Converting Between Systems
- Knowing conversions between Avoirdupois, Household, and Metric units is crucial for pharmacy practice.
- Common conversions:
- 1 lb = 16 oz
- 1 tbsp = 3 tsp = 15 mL
- 1 fl oz = 30 mL
- 1 cup = 240 mL
- 1 pint = 480 mL
Example Conversions
- 5 lb = 5 × 16 oz = 80 oz
- 12 fl oz × 30 mL/fl oz = 360 mL
- 2 tbsp × 15 mL/tbsp = 30 mL
- 1.5 cups × 8 fl oz/cup = 12 fl oz
Safe Medication Measurement Practices
- Pharmacy technicians should advise patients to use pharmacy-provided dosing spoons or cups, not household utensils.
- Accurate dosing prevents medication errors and ensures patient safety.
Key Terms & Definitions
- Avoirdupois system — traditional system using pounds and ounces for weight.
- Household system — uses familiar kitchen measures for volume (tsp, tbsp, cups, pints).
- Metric system — international system using grams and milliliters for precise measurement.
- Fluid ounce (fl oz) — unit of liquid volume, equals 30 mL in Metric.
Action Items / Next Steps
- Practice converting between Avoirdupois, Household, and Metric units.
- Review and use provided dosing tools for accurate medication measurement.
- Prepare for questions on unit conversions and their application in pharmacy.