A pharmacy technician is entering a prescription for an inhaler with 120 metered doses and instructions to take 2 puffs by mouth twice daily. What is the days' supply for this prescription?

To determine the days’ supply for the inhaler prescription, it is essential to analyze how many doses the patient will use each day and then compare that to the total number of doses available in the inhaler.

The inhaler contains 120 metered doses. The prescription indicates that the patient should take 2 puffs twice daily. This means the total number of puffs consumed in one day is:

2 puffs x 2 times = 4 puffs per day.

Next, to find the total number of days the inhaler will last, divide the total number of doses by the daily usage:

120 doses ÷ 4 puffs per day = 30 days.

This calculation shows that the inhaler will provide a sufficient supply for 30 days at the prescribed usage, making it the correct answer. Understanding how to calculate dosage and supply is crucial in pharmacy practice for ensuring patient adherence and proper medication management.