Overview
This lecture explains how to calculate the day supply of a medication, a crucial skill for ensuring patients receive the correct amount for the prescribed duration.
Day Supply Concept
- Day supply represents the number of days a dispensed medication will last if taken as prescribed.
- To calculate day supply, you'll need the dose, frequency, and total quantity dispensed.
Day Supply Calculation Formula
- The basic formula:
Day supply = Total quantity dispensed ÷ (Dose × Frequency per day)
Example 1: Tablet Prescription
- Sig code: "1 tab po bid", Dispense: 60 tablets.
- Interpretation: Take 1 tablet by mouth twice daily.
- Daily dose: 1 tablet × 2 times/day = 2 tablets/day.
- Day supply: 60 tablets ÷ 2 tablets/day = 30 days.
Example 2: Nasal Spray Prescription
- Sig code: "2 sprays each nostril QD", Dispense: 60 metered doses.
- Interpretation: 2 sprays in each nostril once daily.
- Daily dose: 2 sprays × 2 nostrils = 4 sprays/day.
- Day supply: 60 sprays ÷ 4 sprays/day = 15 days.
Example 3: Capsule Prescription (Practice Question)
- Sig code: "1 capsule tid", Dispense: 60 capsules.
- Interpretation: 1 capsule three times daily.
- Daily dose: 1 capsule × 3 times/day = 3 capsules/day.
- Day supply: 60 capsules ÷ 3 capsules/day = 20 days.
Key Terms & Definitions
- Day Supply — Number of days a medication will last based on prescribed directions.
- Sig Code — Prescription shorthand indicating dosage instructions (e.g., "bid" means twice daily, "tid" means three times daily).
- Total Daily Dose — Total amount of medication taken per day.
Action Items / Next Steps
- Practice calculating day supply problems for various dosage forms and instructions.