Due to legislation effective 1/1/2011 a prescription is required for over the counter medicines purchased using a (healthcare) Flexible Spending Account. Many physicians are not willing to write a prescription for over the counter medicines, and if they are willing, they may charge a fee that is generally higher than the cost of the over the counter medicine. The healthcare legislation has many benefits, but has some kinks that need worked out, this is one of them.
HR 2529 addresses this issue specifically.