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Modafinil is a central nervous system (CNS) stimulant. It is primarily used to promote wakefulness and alertness in persons with narcolepsy , a condition that causes excessive sleepiness and cataplexy (episodes of sudden loss of muscle control).


Modafinil is an improvement over amphetamines in the treatment of narcolepsy. It promotes wakefulness, but has less pronounced side effects than amphetamines. Modafinil acts to combat excessive daytime sleepiness (EDS) and cataplexy, the leading symptoms of narcolepsy, by stimulating sleep-suppressing peptides (orexins) in the brain.


Although primarily indicated for the treatment of narcolepsy, modafinil is also used to treat some forms of sleep apnea . Experimentally, modafinil is being evaluated in the treatment of Alzheimer's disease , depression , attention-deficit hyperactivity disorder (ADHD ), and fatigue associated with multiple sclerosis .

Recommended dosage

Modafinil is taken by mouth in tablet form. It is prescribed by physicians in varying dosages, and is usually taken once a day, in the morning.


In some patients, modafinil may be habit forming. When taking the medication, it is important to follow physician instructions precisely. Modafinil may cause clumsiness and impair clarity of thinking. Persons taking this medication should not drive a car or operate machinery until they know how the stimulant will affect them. Patients should avoid alcohol while taking modafinil. It can exacerbate the side effects of alcohol and other medications.

Modafinil may not be suitable for persons with a history of liver or kidney disease, mental illness, high blood pressure, angina (chest pain ), irregular heartbeats, or other heart problems. Before beginning treatment with modafinil, patients should notify their physician if they consume a large amount of alcohol, have a history of drug use, are pregnant, or plan to become pregnant. Patients who become pregnant while taking modafinil should inform their physician.

Side effects

Research indicates that modafinil is generally well tolerated. However, modafinil may case a variety of usually mild side effects. Headache , nausea, and upset stomach are the most frequently reported side effects of modafinil. Other possible side effects include excessive difficulty sleeping, nervousness, depression, diarrhea, dry mouth, runny nose, neck pain or stiffness, back pain , loss of appetite, and confusion.

Other, uncommon side effects of modafinil can be potentially serious. Persons taking modafinil who experiences any of the following symptoms should immediately contact their physician: irregular heartbeat, unusually rapid heartbeat, shortness of breath, hives or rashes, chest pain, persistent or severe headache, and persistent fever, pain, or other sign of infection.


Modafinil may have negative interactions with some anticoagulants (blood thinners), antidepressants, antifungals, antibiotics, and monoamine oxidase inhibitors (MAOIs). Seizure prevention medication, diazepam (Valium), phenobarbital (Luminal, Solfoton), phenytoin (Dilantin), propranolol (Inderal), and rifampin (Rifadin, Rimactane) may also adversely react with Modafinil.

Furthermore, modafinil may decrease the effectiveness of oral contraceptives (birth control pills). Patients should consult their physicians about using alternative methods of birth control while taking modafinil, and for at least one month after ending treatment.



Parker, James N., and Philip N. Parker. The Official Patient's Sourcebook on Narcolepsy. San Diego: ICON Health, 2002.


"Drug Information, Modafinil (Systemic)." MEDLINE Plus Health Information. National Library of Medicine. February 10, 2004 (May 23, 2004). <>.


Center for Narcolepsy. 701B Welch RoadRoom 146, Palo Alto, CA 94304-5742. (650) 725-6517; Fax: (650) 725-4913. <>.

Adrienne Wilmoth Lerner

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