Question About Prescription Due Date After Filling A 28-Day Supply

Answer

You're spot on with the date calculation you wrote in your question.

If you filled a 28-day supply of your prescription on 11/18/2022, you are 'due' for your next fill on 12/16/2022. Since your pharmacy has indicated that you can fill 2 days early from your 'due date', that would be 12/14/2022.

Prescription 'Due' Dates

There is often a lot of confusion surrounding prescription due dates, and when something can be filled. This generally is more of a problem with controlled substances due to ambiguity with federal and state laws, as well as individual pharmacy policies.

This is a topic we have written about several times in the past (here is a description of how your pharmacist calculates day supply and another example of a specific situation regarding controlled substances).

I think the easiest way to describe when you are legally 'due' for a prescription refill is that it is the first day in which you will not have a dose of medication to take.

For example, if you received a 7-day supply of medication on 11/7/2022, a Monday, you are 'due' for a refill on 11/14/2022, the next Monday, as that would be the first day in which you have no medication left to take.

Now, you may be able to fill your medication a little early from the actual 'due' date, but this will vary on several different factors. I always highly recommend talking directly to your pharmacy about when you can refill your medication.

Due Date After A 28-Day Supply Fill

In your example, you filled a 28-day supply prescription on 11/18/2022. The first day you would be without medication (assuming you took it consistently), would be 12/16/2022. That is your 'due' date.

In the calendar below, I list off the days (I am assuming one dose per day, but the concept is applicable regardless of how many doses you take per day) showing the due date of 12/16/2022.

If your pharmacy said they will fill it two days early, as you stated, that would be 12/14/2022.

Final Words

I really try to emphasize with these types of questions the importance of talking to your pharmacy.

There are a lot of factors that can influence prescription fill dates.

As one example, in New York State, the law states you can fill a controlled substance as long as you have no more than a 7-day supply on hand, but your prior fill history, and the policies of your prescriber and pharmacy, can alter the day you can actually fill your medication.

I hope you found this helpful! Please feel free to write back out anytime.