CHICAGO (CBS) — Flu season is ramping up and for the first time in 20 years, the FDA has approved a new drug to battle the bug.

Xofluza (baloxavir marboxil) works by blocking an enzyme in the flu virus and stopping it from replicating.

It’s similar to Tamiflu. It’s meant to be taken within the first 48 hours of the illness. Unlike that drug, Xofluza only needs a single dose.

Studies showed it reduced symptoms by more than a day. Xofluza is expected to be made available in the next few weeks.