Modalert 200mg Australia (Modafinil) is a medication that's used to treat excessive sleepiness from narcolepsy, obstructive sleep apnea, and shift work sleep disorder. It's usually taken in the morning and is a first-choice option for treating these conditions. Narcolepsy is a sleep disorder that affects the brain's natural sleep-wake cycle. It can cause extreme daytime sleepiness and make it hard to stay awake during work, school or other activities.