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Calculating the days supply of medication becomes more complex when the dose changes during a cycle. This practice exercise helps healthcare professionals and students understand how to accurately determine the total days a prescription will last when doses are adjusted mid-cycle.
Understanding the Scenario
Suppose a patient is prescribed a medication that initially requires a dose of 50 mg daily. After two weeks, the dose is increased to 75 mg daily. The prescription is for a total of 30 tablets, with each tablet containing 50 mg. How many days will the medication last?
Step-by-Step Calculation
Follow these steps to determine the total days supply:
- Step 1: Calculate the total amount of medication dispensed.
- Step 2: Determine the total amount used during each phase of the dose change.
- Step 3: Calculate the days covered by each phase.
- Step 4: Sum the days from each phase for the total days supply.
Step 1: Total Medication Dispensed
The prescription contains 30 tablets, each with 50 mg, so total medication is:
30 tablets x 50 mg = 1500 mg
Step 2: Medication Use During Each Phase
During the first two weeks (14 days), the patient takes 50 mg daily. After that, the dose increases to 75 mg daily.
Step 3: Calculate Days for Each Phase
Calculate the amount of medication used in each phase:
- First phase: 14 days x 50 mg = 700 mg
- Remaining medication: 1500 mg – 700 mg = 800 mg
Now, determine how many days the remaining 800 mg will last at 75 mg daily:
800 mg ÷ 75 mg ≈ 10.67 days
Step 4: Total Days Supply
Add the days from both phases:
14 days + 10.67 days ≈ 24.67 days
Conclusion
The medication will last approximately 24.7 days, or about 24 days and 16 hours, given the dose change after two weeks. Accurate calculation ensures proper medication management and patient safety.