Column headings are used to indicate which column the list is sorted by and can be clicked to reverse the sort order.

When a user clicks a column to change the sort order, retain the default sort order as a secondary sort. That will define the display order for medications that have the same attribute value as the new sort. For example, suppose the default display for a list of current medications is with the most recent start date at the top. If the user then sorts that list by 'started', the 'started' medications will be listed with the most recent start date at the top.