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Fall means the start of flu season. And considering that last year was one of the worst flu seasons ever, it's really not something you want to mess with.

This might help: The Food and Drug Administration (FDA) just approved the first flu medication in over 20 years: Xofluza.

What is Xofluza?

"Xofluza is a one-dose antiviral flu treatment medication meant to be taken within 48 hours of flu symptoms," says Elisabeth Farnum, M.D., associate medical director at Doctor On Demand. "Xofluza works by stopping the virus from multiplying in the body, which can shorten the course and somewhat decrease the intensity (of the flu)," says Dr. Farnum.

How does it compare with other antiviral flu meds on the market?

You've probably heard of these other medications on the market: Tamiflu, Relenza, and Rapivab, which all work by treating flu symptoms within two days of getting sick, according to the Centers for Disease Control and Prevention (CDC).

But they each have drawbacks. Tamiflu (in pill or liquid form) must be taken twice a day for five days. Relenza is a powder that must be inhaled twice a day for five days and isn't recommended for people with breathing problems like asthma. And Rapivab is a single dose given intravenously every 15 to 30 minutes.

Xofluza is a single-dose medication—that's it. And it may kick in quicker than the other antivirals, says Dr. Farnum.

But there are a couple of negatives.

"There are also some studies that have indicated that resistance may develop a bit more easily with Xofluza over time, whereas there is no significant resistance to Tamiflu," says Dr. Farnum.

And it may cost a pretty penny. "Xofluza will probably cost about $150—and since it's so new, it may not be covered by insurances just yet," says Dr. Farnum. "Tamiflu is generic, mostly covered by insurance, and in the $50 (with coupons) to $130 range."

Should you take it?

The key takeaway about Xofluza is that it's a treatment, not a preventive medication. So while getting the flu shot can be a drag, it's still the best way to prevent yourself from getting the flu. (Hate getting shots? No excuse. There's a needle-free version called FluMist.) Bottom line: Xofluza is not a replacement for getting a flu shot, but it's worth talking to your doctor about if you do come down with the flu despite your best efforts.