With one month left to exhaust any money remaining in flexible spending accounts, it s time for the annual ritual of stocking up on aspirin, re-ordering contact lenses and squeezing in one more round of skincare treatment . But starting next year, new rules will make that drugstore shopping spree a lot harder -- which means re-thinking how you spend this year s money, and how much you allocate for 2011.

The new rules are a hassle. Starting in January, many over-the-counter medications will not be covered by FSAs without a prescription. If you want a tax break for Tylenol, you ll need a prescription from your doctor. Yes, that defeats the point of over-the-counter, and doctors aren t exactly eager to spend their days signing off on routine meds, says Dr. Roland Goertz, president of the American Academy of Family Physicians, which represents 94,000 doctors. But consumers who don t want to jump through these hoops could lose about $500 to $1,000 of tax savings each year, says Thomas Harte, a board member with the National Association of Health Underwriters.

As it is, consumers don t always make the most of their FSAs. Only one in three eligible employees participate, according to Mercer, and some don t spend all the money they set aside. (The excess returns to the employer, who typically uses it to offset the cost of administering the FSA program.) Last year, the average participant who forfeited funds left $43 unspent not a fortune, but up 54% from the year before. Under the new rules, it s likely that amount will keep growing, says Sheryl Garrett, a fee-only certified financial planner or that consumers will simply stop using the FSA altogether and give up the tax break.

there s a tentative list here, there are new strategies for using the remainder of this year s FSA money. Specifically: Stock up now on medications that will require a prescription next year, and delay any non-urgent doctor visits until January. That way, this year s money will pay for those drugstore buys, next year s money will pay for the check-up, and you ll have a chance to get prescriptions for anything you might need early in the year, says Harte.

And while you re at the doctor, ask about her policy for writing prescriptions for over-the-counter medications. Many doctors will agree, says Goertz, but some, frustrated by the paperwork and time required, will decline. Some may require a patient visit before writing a prescription, which means consumers could have to budget more for co-pays, and other doctors might levy an extra fee for the service. This should all be part of the equation for employees who can still adjust their FSA allocation for next year, experts say: If you re using that money primarily for drugstore spending, you may find the tax savings isn t worth the hassle.