Modafinil treats certain sleep disorders including narcolepsy and shift work sleep disorder. Avoid drinking alcohol while taking this medication.

Modafinil Overview


Modafinil is a prescription medicine used to treat adults with certain sleep disorders including narcolepsy and shift work sleep disorder. Modafinil is in a class of drugs known as central nervous system (CNS) stimulants, which alter brain activity to promote wakefulness.

This medication comes in tablet form and is usually taken once a day in the morning.
Common side effects of modafinil include back pain, headache, nervousness, and nausea.

Modafinil Genetic Information

CYP2D6 is a protein in your body that is involved in the elimination of modafinil and other drugs from your body. Some patients have less of this protein in their bodies, affecting how much of the drug gets eliminated. Levels of CYP2D6 can vary greatly between individuals, and those having less of this protein are known as "poor metabolizers." 

CYP2D6 testing is done to determine whether you are a poor metabolizer. If you are a poor metabolizer, the levels of modafinil in your blood can become too high. As a result you may be at an increased risk of having more side effects from modafinil. 

Your doctor may adjust your dose of modafinil if you are a poor metabolizer.

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  • Attention Deficit Disorder With Hyperactivity
  • Fatigue
  • Narcolepsy

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Modafinil Cautionary Labels


Uses of Modafinil

Modafinil is a prescription medicine used to improve wakefulness in adults who are very sleepy due to one of the following diagnosed sleep disorders:

  • narcolepsy
  • obstructive sleep apnea (OSA).  Modafinil is used with other medical treatments for this sleep disorder.
  • shift work disorder (SWD)

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Modafinil Brand Names

Modafinil may be found in some form under the following brand names:

Modafinil Drug Class

Modafinil is part of the drug class:

Side Effects of Modafinil

Modafinil may cause serious side effects. Stop taking modafinil and call your doctor right away or get emergency help if you get any of the following:

  • a serious rash or serious allergic reaction
  • psychiatric (mental) symptoms, including:
    • depression
    • feeling anxious
    • hearing, seeing, feeling, or sensing things that are not really there (hallucinations)
    • an extreme increase in activity and talking (mania)
    • thoughts of suicide aggressive behavior
    • other mental problems
  • symptoms of a heart problem, including chest pain, abnormal heart beats, and trouble breathing

Common side effects include:

  • back pain
  • headache
  • nausea
  • feeling nervous
  • stuffy nose
  • diarrhea
  • feeling anxious
  • dizziness
  • upset stomach
  • trouble sleeping

Tell your doctor if you get any side effect that bothers you or that does not go away while taking modafinil. Some effects of modafinil on the brain are the same as other medicines called “stimulants”. These effects may lead to abuse or dependence on modafinil.

Modafinil Interactions

Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Modafinil and many other medicines can interact with each other, sometimes causing side effects. Modafinil may affect the way other medicines work, and other medicines may affect how modafinil works. Your dose of modafinil or certain other medicines may need to be changed. Especially, tell your doctor if you use or take a hormonal birth control method such as:

  • birth control pills
  • shots
  • implant
  • patches
  • vaginal rings
  • intrauterine devices (IUDs)

Hormonal birth control methods may not work while you take modafinil. Women who use one of these methods of birth control may have a higher chance for getting pregnant while taking modafinil. This risk lasts for one month after stopping modafinil. Talk to your doctor about birth control choices that are right for you while taking modafinil.

Modafinil Precautions

Do not drive a car or do other dangerous activities until you know how modafinil affects you.

People with sleep disorders should always be careful about doing things that could be dangerous.

Do not change your daily habits until your doctor tells you it is okay.

You should avoid drinking alcohol. It is not known how drinking alcohol will affect you when taking modafinil.

Do not take modafinil if you:

  • are allergic to any of its ingredients.  
  • have had a rash or allergic reaction to either modafinil or armodafinil. These medicines are very similar.

Modafinil Food Interactions

Grapefruit and grapefruit juice may interact with modafinil and lead to potentially dangerous effects. Discuss the use of grapefruit products with your doctor.

Inform MD

Tell your doctor about all of your medical conditions including, if you:

  • have a history of mental health problems, including psychosis
  • have heart problems or had a heart attack
  • have high blood pressure. Your blood pressure may need to be checked more often while taking modafinil.
  • have liver or kidney problems
  • have a history of drug or alcohol abuse or addiction
  • are pregnant or planning to become pregnant. It is not known if modafinil will harm your unborn baby.
  • are breastfeeding. It is not known if modafinil passes into your milk. Talk to your doctor about the best way to feed your baby if you take modafinil.

Modafinil and Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant. It is not known if modafinil will harm your unborn baby. Modafinil has not been studied in pregnant women. Modafinil should be used during pregnancy only if clearly needed.

Modafinil and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed. It is not known if modafinil is excreted in human breast milk or if it will harm your nursing baby.

Modafinil Usage

  • Take modafinil exactly as prescribed by your doctor. Your doctor will prescribe the dose of modafinil that is right for you. Do not change your dose of modafinil without talking to your doctor.
  • Your doctor will tell you the right time of day to take modafinil. 
  • People with narcolepsy or obstructive sleep apnea (OSA) usually take modafinil one time each day in the morning.
  • People with shift work disorder (SWD) usually take modafinil about 1 hour before their work shift.
  • Do not change the time of day you take modafinil unless you have talked to your doctor. If you take modafinil too close to your bedtime, you may find it harder to go to sleep.
  • You can take modafinil with or without food.

Modafinil Dosage

Take modafinil exactly as prescribed by your doctor. Follow the directions on your prescription label carefully. Your doctor will determine the best dose for you. The dosage of modafinil must be individualized.

The recommended dose of modafinil is 200 mg given once a day.

For patients with narcolepsy and obstructive sleep apnea (OSA), modafinil should be taken as a single dose in the morning.

For patients with shift work disorder (SWD), modafinil should be taken approximately 1 hour prior to the start of their work shift.

Modafinil Overdose

If you take more than your prescribed dose or if you take an overdose of modafinil, call your doctor or poison control center right away.
 Symptoms of an overdose of modafinil may include:

  • Trouble sleeping
  • Restlessness
  • Confusion
  • Feeling disoriented
  • Feeling excited
  • Hearing, seeing, feeling, or sensing things that are not really there (hallucinations)
  • Nausea and diarrhea
  • A fast or slow heartbeat
  • Chest pain
  • Increased blood pressure

Other Requirements

  • Store modafinil at room temperature between 68° and 77° F (20° and 25° C).
  • Keep modafinil and all medicines out of the reach of children.