What is Modafinil: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Dec 30, 2020

Modafinil is a non-amphetamine prescription stimulant that helps people with sleep disorders stay awake during the day. Healthcare professionals call it a wakefulness-promoting drug. Modafinil only helps relieve daytime fatigue or sleepiness. It does not treat the underlying sleep problem.

Modafinil overview

BRAND NAMES:

  • Provigil

Generic Names:

  • Modafinil

Uses:

  • Relieves daytime sleepiness and fatigue due to narcolepsy, sleep apnea, and shift work sleep disorder.

Therapeutic Classes:

  • CNS Stimulant

Forms:

  • Tablet

How it’s taken:

  • By mouth

What is Modafinil used for?

Modafinil treats excessive sleepiness caused by narcolepsy, obstructive sleep apnea, or shift-work disorder. Healthcare professionals sometimes use it off-label for fatigue or sleepiness caused by other conditions such as multiple sclerosis, Parkinson’s disease, or major depressive disorder.

What form(s) does Modafinil come in

  • Tablet

    • 100 mg

    • 200 mg

What are common Modafinil doses?

  • For excessive sleepiness due to narcolepsy or obstructive sleep apnea: 200 mg tablet taken once in the morning 

  • For excessive sleepiness due to shift work sleep disorder: 200 mg tablet taken once per day one hour before the start of the work shift

Common Modafinil prescriptions

  • Modafinil
    30 tablets bottle

  • Modafinil
    100mg tablet

  • Modafinil
    200mg tablet

How to take Modafinil

  • Your doctor will tell you how much medicine to use. Do not use more than directed.

  • Please read the Medication Guide that comes with this drug.

  • If used for daytime wakefulness, take one dose in the morning. 

  • If used to stay awake during shift work, take the tablet one hour before the start of the work shift.

  • Do not change the time when tablets are taken without talking to the prescriber first.

  • Do not take a modafinil dose late in the day.

  • Modafinil tablets can be taken with or without food.

  • Swallow the tablet whole with a drink of water.

  • Store modafinil tablets out of the reach of children.

What to do if you miss a dose of Modafinil

  • Ask the prescriber what to do if a dose is missed.

  • If it’s still early, take a dose as soon as it’s remembered.

  • If more than half the day has passed, the dose should be skipped. Taking the dose later in the day may cause sleeping problems at night. 

  • Do not take more than one dose in a single day.

Modafinil contraindications

  • You should not use this medicine if you have had an allergic reaction to modafinil or armodafinil.

Modafinil warnings

  • Before starting modafinil, tell the prescribing healthcare professional about all the medical conditions you have, particularly:

    • Liver problems

    • Kidney problems

    • Heart problems

    • A past heart attack

    • High blood pressure

    • A history of mental illness

    • A history of drug abuse

  • Tell the healthcare provider if you’re pregnant, planning to get pregnant, or get pregnant while on modafinil. There is an increased risk of birth defects when pregnant women take modafinil.

  • Tell the prescriber if you are breastfeeding or planning to breastfeed. The provider may choose to switch to a different stimulant to address excessive sleepiness.

  • Modafinil can cause serious problems, including:

    • Psychiatric symptoms such as mood changes, aggression, psychosis, mania, and delusions

    • Sudden difficulty breathing (bronchospasm)

    • Heart irregularities like chest pain, palpitations, heart rate changes, or high blood pressure

    • Severe allergic or drug reactions

  • Your doctor will check your progress and the effects of this medicine at regular visits. Your blood pressure may need to be checked more often while taking this medicine. Keep all appointments. 

  • Modafinil may not fully relieve excessive sleepiness. If you are sleepy, fatigued, or not alert, avoid driving, using machines, or doing anything else that could be hazardous, even if you’ve taken your daily dose of modafinil.

  • This medicine can be habit-forming. Do not use more than your prescribed dose. Call the prescriber if you think your medicine is not working.

  • Do not discontinue any previous treatments unless instructed to do so by the doctor.

Modafinil interactions

  • Modafinil can interact with many different types of drugs. Make sure the prescriber knows about all the prescription drugs, over-the-counter medications, and supplements being taken.

  • Before any other healthcare professional prescribes any new medications, tell that provider about modafinil.

  • Modafinil’s most significant drug interactions are with hormonal contraceptives that contain ethinyl estradiol. Modafinil reduces its effectiveness, and so increases the risk of pregnancy. To keep from getting pregnant, use another form of birth control while you are using this medicine and for one month after your last dose.

  • Do not drink alcohol while you are using this medicine.

Modafinil side effects

Serious side effects

Talk to a doctor if you notice any signs or symptoms of a possible serious side effect, including:

  • Unusual thoughts or behaviors, hallucinations, delusions, thoughts of hurting yourself 

  • Unusual aggressiveness, agitation, excitement, confusion, or mood changes (such as depression or anxiety)

  • Chest pain, palpitations, difficulty breathing, fast, slow, or pounding heartbeat

  • Sudden difficulty breathing

  • Blistering, peeling, or red skin rash.

  • Fever, body-wide skin rash, hives, swollen lymph nodes, dry or cracked lips

  • Allergic reaction: Skin rash, skin redness, skin swelling, severe itching, swelling of the face, mouth, or tongue, trouble breathing, hoarseness, trouble swallowing, chest pain, feeling faint

Less serious side effects

  • Headache

  • Nausea

  • Nervousness

  • Runny nose

  • Anxiety

  • Trouble sleeping

Sources:

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