Modafinil is a drug that helps people who are too sleepy during the day because of conditions like narcolepsy, obstructive sleep apnea, or shift work sleep disorder stay awake and alert. The exact way it works is not fully known, but it is thought to be a central nervous system stimulator. It is thought that modafinil works by making neurotransmitters like dopamine, norepinephrine, and histamine work more efficiently. These neurotransmitters help to keep you awake and less tired. It comes in pill form and is usually taken by mouth once a day in the morning. Modafinil is known for having a long half-life and a lower chance of being abused than some other stimulant drugs. But it can still have side effects like headaches, nausea, anxiety, and trouble sleeping, so it should only be used with the help of a doctor.