Modafinil, also known by its brand name Provigil, is a central nervous stimulant that has been approved by the U.S. Food and Drug Administration to treat daytime sleepiness in individuals who have conditions that include narcolepsy, shift work disorder, and sleepiness caused by medical conditions such as sleep apnea. However, it is also sometimes misused without a prescription.

Plenty of people misuse cognitive-enhancing or psychostimulant drugs in a nonprescription capacity in order to increase productivity, combat fatigue, and help with intellectual challenges. Although abuse of cognitive-enhancing drugs like amphetamine, methylphenidate, and modafinil is typically associated with university students—an estimated 7% to 20% of U.S. college students have reported misusing the drugs.

However, it is not uncommon for other groups of people to misuse these drugs as well. For example, 8.9% of surgeons surveyed in Germany reported the nonprescription use of cognitive-enhancing drugs.

Modafinil is supposed to be less addictive than other psychostimulants like amphetamine, but some evidence suggests that dependence and abuse are possible.1 However, modafinil can cause some serious adverse effects and should be taken only when prescribed by a physician.

What Is Modafinil?

Modafinil is sometimes called a “wakefulness-promoting agent.” Researchers believe that this drug works by increasing the synaptic availability of neurotransmitters like monoamines, catecholamines, dopamine, serotonin, adenosine, and noradrenaline. Modafinil affects the hypothalamus, hippocampus, and amygdala which are parts of the brain.

Modafinil is a tablet taken by mouth usually once-a-day.2 Most people who work during the day take the drug in the morning on either a full or empty stomach. However, shift workers who take the drug to promote wakefulness take the drug before their shifts begin.

What Does Modafinil Treat?

Modafinil is used to treat problems with sleep, arousal, and wakefulness. Some conditions treated with modafinil include the following:

  • Narcolepsy
  • Shift-work sleep disorder
  • Obstructive sleep apnea
  • Traumatic brain injury
  • Adjuvant treatment of depression
  • ADHD
  • Sedation due to medications

Adverse Effects

Modafinil’s most common adverse effects include the following:

  • Vomiting
  • Nausea
  • Agitation
  • Anxiety

Other adverse effects include the following:

  • Insomnia
  • Diarrhea
  • Constipation
  • Sweating
  • Hoarseness
  • Difficulty breathing
  • Chest pain
  • Irregular heartbeat
  • Hallucination
  • Rash
  • Blisters
  • Hives
  • Suicidal ideation (thoughts of suicide)

Some of these adverse effects are scary and dangerous so be sure to contact your physician if you experience any of them.

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 1-800-273-8255 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911.

For more mental health resources, see our National Helpline Database.

Additionally, some of these adverse effects such as insomnia, restlessness, chest pain, nausea, and confusion may result from overdose with modafinil. If you suspect an overdose, call emergency services or contact a physician immediately.


Modafinil isn’t for everyone, and before your physician prescribes you this medication, you should inform her of the following:

  • Allergy to modafinil or armodafinil (an enantiomer of modafinil)
  • Antidepressant medications including SSRIs, TCAs, and benzodiazepines
  • Antiseizure medications like phenytoin and carbamazepine
  • Antifungal medications like itraconazole and ketoconazole
  • Illicit drug misuse or dependence
  • Vitamins, nutritional supplements, and herbal supplements

People who have unstable angina or recently had a heart attack shouldn’t be given modafinil. Furthermore, it’s unclear the effect that modafinil has on the seizure threshold. Thus, modafinil should be used with caution in people with epilepsy and other seizure disorders.

There are no long-term studies on the effects of modafinil on the brain. A physician must carefully consider whether to prescribe modafinil and weigh the benefit of its stimulant properties with potentially adverse effects.

Although modafinil is probably less addictive than other stimulants like amphetamines and methylphenidate, it still can likely lead to dependence. 

Please understand that every time a physician makes the decision to prescribe modafinil, this decision is patient specific. In other words, if you’ve prescribed modafinil or any other psychostimulant, this prescription is only for you. You shouldn’t share or sell modafinil—or any prescription drug for that matter. Such diversion is harmful and illegal. 

A Word From Verywell

Modafinil can be effective for promoting wakefulness when taken as prescribed. Follow your doctor’s instructions. Do not take your medication in a larger dose, more frequently, or for a longer period of time than you have been instructed to do by your doctor.

This medication should also not be used as a substitute for adequate sleep. Continue maintaining good sleep habits and get enough rest each night while you are taking this medication. If you are still struggling to maintain wakefulness even when taking modafinil, talk to your doctor about your symptoms and treatment options.