Thanks for posting in the Apple Support Communities veggiechicklol,
The following may help:
You can change an event’s settings at any time. Double-click an event to open it and make adjustments.
* Set the event’s date and time: Type in the fields.
* Set the event’s time zone: Click the Time Zone pop-up menu, then choose an option. If you don’t see the Time Zone pop-up menu, turn on Time Zone support.
* Keep the event in the same time zone (even if the calendar’s time zone changes): Click the Time Zone pop-up menu, then choose Floating.
* Make the event last all day: Select “all-day.”
* Make the event a multi-day event: Select “all-day,” then specify start and end dates in the “from” and “to” fields.
* Make the event a repeating event: Click the “repeat” pop-up menu, then choose an option.
* Add a link to an event: Type in the “url” field.
* Add a note to an event: Type in the “note” field.
Add and edit an event in a calendar on iCloud.com
Try putting the Prescription ID number, in the Notes field and see if that offers a solution.
Cheers!