Modafinil 200 mg tablet is a prescription medication used to treat excessive sleepiness caused by narcolepsy, obstructive sleep apnea, and shift work sleep disorder. It works by promoting wakefulness and alertness in the brain. The tablet is white to off-white, capsule-shaped, and debossed with "MOD" on one side and "200" on the other. It should be taken orally with or without food, usually once a day in the morning. The dosage may vary depending on the individual's condition and response to treatment. Common side effects include headache, nausea, nervousness, and insomnia. It is important to follow the doctor's instructions and not exceed the recommended dosage.