Take modafinil at the same times each day to avoid missing any doses.
The most common side-effects include headache, feeling sick (nausea) and feeling dizzy.
You should not become pregnant whilst taking modafinil. Ask your doctor about which contraceptive methods are suitable for you while you are taking modafinil - hormonal contraceptives are not suitable.
|Type of medicine||A central nervous system stimulant|
|Used for||Daytime sleepiness associated with narcolepsy in adults|
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
Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking modafinil it is important that your doctor knows:
- If you are pregnant, trying for a baby or breastfeeding.
- If you have any problems with the way your liver works or any problems with the way your kidneys work.
- If you have a heart condition or high blood pressure (hypertension).
- If you have ever had a mental health problem such as depression, psychosis or mania.
- If you have ever had a problem with drug or alcohol misuse.
- If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
- If you have ever had an allergic reaction to a medicine.
Clinical author's note Michael Stewart 01/03/2020: Based on post-marketing reports from the USA, modafinil (Provigil®) may harm an unborn child. Modafinil should not be used during pregnancy. Women of childbearing potential must use effective contraception during treatment with modafinil and for two months after stopping. Discuss with your doctor which forms of contraception are suitable for you, as hormonal contraceptives are made less effective by modafinil. Alternative treatment options for narcolepsy should be used during pregnancy, such as behaviour modifications, good sleeping habits and scheduled daytime naps.
How to take modafinil
- Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about modafinil and will provide you with a full list of the side-effects which you may experience from taking it.
- Take the tablets exactly as your doctor tells you to. There are two strengths of tablet available - 100 mg and 200 mg. When you first start modafinil it is usual to be prescribed a dose of 200 mg daily. You may be asked to take this as a single dose of 200 mg in the morning, or divided into 100 mg in the morning and 100 mg at midday. Your doctor or pharmacist will tell you which is right for you. Your dose may be increased after a little while, depending upon your symptoms.
- Take your doses with a drink of water to help you swallow the tablet. Do not break or crush the tablet - it should be swallowed whole. You can take modafinil before or after food.
- If you forget to take a dose, miss out the forgotten dose completely but make sure that you remember to take your next dose when it is due. Do not take two doses together to make up for a forgotten dose.
Getting the most from your treatment
- Keep your regular appointments with your doctor so that your progress can be monitored. You may need to have your blood pressure and heart rate checked regularly.
- Modafinil can cause blurred vision or dizziness in some people and therefore it may affect your ability to use tools or machines, so take care when using them. Sleepiness associated with your condition can add to this.
- Taking modafinil is not a replacement for a good sleep routine. It is still important that you aim to get around eight hours of sleep at night if possible. You should try to go to sleep and get up at about the same time each day.
- In the UK, you are required by law to let the Driver and Vehicle Licensing Authority (DVLA) know if you are diagnosed with narcolepsy. You may be allowed to drive again when your symptoms are well controlled with medication, but you will need to have regular reviews. Your doctor will advise you about this.
- Modafinil should not be used during pregnancy. Women of childbearing potential must use effective contraception during treatment with modafinil and for two months after stopping.
- Hormonal contraceptives, including oral contraceptive pills, implants, intrauterine contraceptive devices (IUCDs) and contraceptive patches, are less effective when used with modafinil and are therefore not recommended. Speak to your doctor about which contraceptive methods are suitable for you while you are taking modafinil.
- If you are planning to become pregnant you should stop taking modafinil and try alternative treatment options such as good sleep habits and scheduled daytime naps.
- If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking modafinil.
Can modafinil cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with modafinil. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.
|Common modafinil side-effects||What can I do if I experience this?|
|Headache||This usually passes within a day or so, but in the meantime, ask your pharmacist to recommend a suitable painkiller. If the headache continues, speak with your doctor|
|Dry mouth||Try chewing sugar-free gum or sucking sugar-free sweets|
|Feeling sick (nausea), indigestion, stomach ache||Stick to simple meals - avoid rich or spicy foods|
|Diarrhoea||Drink plenty of water to replace lost fluids|
|Constipation||Try to eat a well-balanced diet and drink several glasses of water each day|
|Feeling dizzy or tired, blurred vision||Take special care when using tools or machines|
|Flushing, loss of appetite, nervousness, difficulty sleeping, anxiety, depression, confusion or confused thinking, chest pain, fast heartbeat, numbness or tingling feelings||Speak with your doctor if any of these continue or become troublesome|
Important: if you experience any of the following symptoms, stop taking modafinil and contact your doctor for advice straightaway:
- A rash or blisters on the skin.
- Any changes to your mood, behaviour, or thinking.
- Any suicidal thoughts, or thoughts about harming yourself.
If you experience any other symptoms which you think may be due to the tablets, speak with your doctor or pharmacist for further advice.
How to store modafinil
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.
Important information about all medicines
Never take more than the prescribed dose. If you suspect that you or someone else might have 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.
If you buy any medicines, check with a pharmacist that they are suitable to take with your other medicines.
Do not 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 and references
Manufacturer's PIL, Modafinil (Provigil®) 100 mg and 200 mg tablets; Teva Pharma B.V., The electronic Medicines Compendium. Dated February 2020.
British National Formulary, 79th Edition (Mar 2020); British Medical Association and Royal Pharmaceutical Society of Great Britain, London.