• Take modafinil at the same times each day to avoid missing any doses.
  • Do not drive while you are taking modafinil without discussing it first with your doctor.
  • Important: Hormonal contraceptives may be less effective when used with modafinil. Ask your doctor about which contraceptive methods are suitable for you while you are taking modafinil.
Type of medicine Stimulant
Used for Daytime sleepiness associated with narcolepsy in adults
Also called Provigil®
Available as Tablets

Narcolepsy is a long-term problem that affects your sleep. You feel excessively tired during the daytime but have disturbed night time sleep. You can also have sleep attacks where you fall asleep at inappropriate times during the day without any warning.

Although there is no cure for narcolepsy, modafinil can help to control your symptoms. Modafinil works by stimulating the central nervous system to increase your alertness and reduce excessive sleepiness during the day.

Before taking modafinil make sure your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have liver, kidney or heart problems.
  • If you have high blood pressure or chest pains.
  • If you have mental health problems such as anxiety, depression, psychosis or mania.
  • If you have ever had a problem with drug or alcohol misuse.
  • If you are taking other medicines, including those available to buy without a prescription, herbal and complementary medicines.
  • If you have ever had an allergic reaction to this or any other medicine.
  • Before starting this treatment, read the manufacturer's printed information leaflet from inside the pack.
  • Take modafinil exactly as your doctor has told you.
  • You may take modafinil before or after food. Swallow the tablets whole with a drink of water.
  • Take modafinil at the same times each day to avoid missing any doses.
  • If you forget to take a dose, do not worry, just take the next dose when it is due. Do not take two doses together to make up for a forgotten dose.
  • Keep your regular appointments with your doctor so your progress can be monitored. You may need to have your blood pressure and heart rate checked regularly.
  • Modafinil may cause blurred vision or dizziness in some people and therefore it may affect your ability to drive or operate machinery. Sleepiness associated with your condition will also affect your ability to perform these tasks, so do not drive without discussing it first with your doctor.
  • Important: Hormonal contraceptives, including oral contraceptive pills, implants, IUDs (intra-uterine devices) and contraceptive patches, may be less effective when used with modafinil. Speak to your doctor about which contraceptive methods are suitable for you while you are taking modafinil and for the two months after you finish taking it.
  • If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking modafinil.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common side-effects - these affect less than 1 in 10 people who take this medicine What can I do if I experience this
Headache Ask your pharmacist to recommend a suitable painkiller. If the headache continues, speak with your doctor
Dry mouth Try chewing sugar-free gum or sugar-free sweets
Feeling sick, indigestion, stomach ache Eat little and often. Stick to simple or bland foods - avoid rich and spicy foods
Diarrhoea Drink plenty of water to replace lost fluids
Constipation Try to eat a well balanced diet containing plenty of fibre and drink 6-8 glasses of water each day
Dizziness, blurred vision, tiredness Make sure your reactions are normal before doing anything which could be dangerous if you were not fully alert
Flushing, loss of appetite, nervousness, difficulty sleeping, anxiety, depression, confusion or confused thinking, chest pain, fast heartbeat, numbness or tingling Speak to your doctor if any of these continue or become troublesome

If you experience any other symptoms which you think may be due to this medicine, discuss them with your doctor or pharmacist.

Important: If you experience any of the following symptoms, stop taking modafinil and contact your doctor for advice straight away:

  • A severe rash or blistering of the skin.
  • Sudden wheeziness, difficulty in breathing, or any swelling of your face mouth or throat.
  • Suicidal thoughts, or thoughts about harming yourself.
  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

  • If you buy any medicines check with a pharmacist that they are safe to take with your other medicines.
  • Never take more than the prescribed dose. If you suspect that you or someone else has taken an overdose of this medicine go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.
  • This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
  • Never keep out of date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
  • If you have any questions about this medicine ask your pharmacist.

Further reading & references

  • British National Formulary; 62nd Edition (Sep 2011) British Medical Association and Royal Pharmaceutical Society of Great Britain, London
  • Manufacturer's PIL, Provigil® 100 mg Tablets, Provigil 200 mg Tablets; Manufacturer's PIL, Provigil® 100 mg Tablets, Provigil 200 mg Tablets, Cephalon (UK) Limited, electronic Medicines Compendium. Dated January 2011.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Last Checked:
Document ID:
1083 (v24)
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