Modafinil 200 mg tablets modulate the levels of chemical messengers in your brain and exert a stimulant effect to reduce extreme sleepiness. It is important to follow the doctor’s directions and not exceed the prescribed dosage. This drug should not be taken by people with a history of heart problems, liver disease, or kidney disease. It is also not recommended for use in children under 18 years of age since it may cause serious side effects.