5 Prescription Quantities and Days’ Supply Free Online FlashCards

How do prescription quantity and days’ supply differ?

Quantity is the amount dispensed; days’ supply is the estimated number of days it lasts when used as directed. They are related but not interchangeable.

How do you calculate quantity for a regularly scheduled medication?

Multiply the amount per dose by doses per day and by the number of days: $\text{quantity} = \text{amount per dose} \times \text{doses per day} \times \text{days}$.

How do you calculate days’ supply?

Divide the quantity dispensed by the amount used per day: $\text{days’ supply} = \text{quantity dispensed} \div \text{amount used per day}$.

Why must units stay consistent in a quantity calculation?

Keep units consistent throughout the calculation: count tablets when the dose is in tablets, and use milliliters when the dose is in milliliters.

How many tablets are needed for 1 tablet 3 times daily for 10 days?

Daily use is $1 \times 3 = 3$ tablets. For $10$ days, dispense $3 \times 10 = 30$ tablets.

What quantity covers 5 mL twice daily for 7 days?

Daily use is $5 \times 2 = 10$ mL. For $7$ days, the quantity is $10 \times 7 = 70$ mL.

How should days’ supply be calculated for PRN directions?

Use the maximum permitted daily use, based on the shortest allowed interval, unless applicable billing rules or documented instructions specify otherwise.

What is the days’ supply for 24 capsules taken every 4–6 hours as needed?

At the shortest interval, maximum use is $24 \div 4 = 6$ capsules per day. The days’ supply is $24 \div 6 = 4$ days.

What should you do if PRN directions do not establish maximum daily use?

Seek clarification rather than guessing if the prescription does not allow the maximum daily use to be determined.

What should you check when a product comes in a fixed package size?

Use the labeled contents and directions to calculate use, then check package compatibility. Follow applicable requirements and clarify when needed; do not silently change the prescribed quantity.

What is the days’ supply of a 200-actuation inhaler used 2 actuations twice daily?

Daily use is $2 \times 2 = 4$ actuations. A hypothetical inhaler with $200$ usable actuations provides $200 \div 4 = 50$ days’ supply.

How many days’ supply is 1,000 units of insulin at 40 units daily?

U-100 insulin contains $100$ units per mL, so a $10$ mL vial contains $1{,}000$ units. At $40$ units daily, that is $1{,}000 \div 40 = 25$ days.