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Dexamfetamine for narcolepsy and ADHD


Dexamfetamine is prescribed both for adults and for children, but for different conditions.

It can affect your ability to perform skilled tasks - if affected do not drive and do not use tools or machines.

Do not stop taking dexamfetamine without speaking with your doctor first. Stopping it suddenly may cause problems.

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About dexamfetamine

Type of medicine

A stimulant

Used for

Narcolepsy in adults, and attention deficit hyperactivity disorder (ADHD) in children aged 6-18 years

Also known as (UK)


Also known as (USA)

Dextroamphetamine; Dexedrine®, Adderall®

Available as

Tablets, oral solution; modified-release capsules (in US)

Narcolepsy is a long-term problem that affects your sleep. You feel excessively tired during the daytime but have disturbed sleep during the night. You can also have sleep attacks where you fall asleep at inappropriate times during the day without any warning. Although there is no cure, medicines can help to control the symptoms. Dexamfetamine works by stimulating the central nervous system to increase your alertness and reduce excessive sleepiness during the day. You can, however, develop tolerance to dexamfetamine, so other medicines for narcolepsy (such as modafinil) are often preferred.

Dexamfetamine is also sometimes used by specialists to treat children with attention deficit hyperactivity disorder (ADHD). ADHD is a fairly common condition that mainly affects a person's behaviour. People with ADHD show persistent restlessness, impulsiveness and/or inattention. Help is given to understand your emotions and behaviours but where this is insufficient, medicines may be prescribed. Other medicines for ADHD are often preferred but where these are unsuccessful, dexamfetamine can be helpful.

Before taking dexamfetamine

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 (or a child in your care) start taking dexamfetamine it is important that your doctor knows:

  • If you are pregnant, trying for a baby or breastfeeding.

  • If you have a heart condition, or any problems with your blood vessels.

  • If you have any problems with the way your kidneys work.

  • If you have an overactive thyroid gland (hyperthyroidism).

  • If you have high blood pressure.

  • If you have had a mental health problem - for example, psychosis or bipolar disorder.

  • If you have epilepsy.

  • If you have ever had any uncontrollable movements such as a nervous tic, or if you have a condition called Tourette's syndrome.

  • If you have raised pressure in your eyes (glaucoma).

  • If you have ever had a problem with drug or alcohol misuse.

  • If you have an eating disorder such as anorexia nervosa.

  • If you have a rare inherited blood condition called porphyria.

  • If you are taking any other medicines. This includes any medicines 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.

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How to take dexamfetamine

  • Before starting this treatment, read the manufacturer's printed information leaflet from inside the pack. The leaflet will give you more information about dexamfetamine and a full list of side-effects from taking it.

  • Make sure you take dexamfetamine exactly as your doctor tells you to. Your doctor or pharmacist will tell you how many tablets to take and when to take them. It is usual to take 2-4 doses of dexamfetamine each day. Your dose will be on the label of the pack to remind you.

  • When starting your treatment your doctor may give you a small dose and then gradually increase it. This allows your doctor to make sure that you have the dose that helps your condition but avoids unwanted side-effects.

  • It is not important whether you take dexamfetamine before or after food, but try to remember to take your doses at the same times of day, each day. This will help you avoid missing doses. If you do forget to take a dose, do not worry, just remember to take the 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 the regular appointments with your doctor so your progress can be monitored. Your doctor will want to check to ensure that the treatment is helping. There may also be tests that your doctor wants you to have - this is especially the case for children taking dexamfetamine.

  • Do not drink alcohol while you are on dexamfetamine. Alcohol will increase the risk of side-effects so it is not recommended.

  • Before you buy any medicines, check with a pharmacist that they are safe to take with dexamfetamine.

  • If you are a driver, please be aware that dexamfetamine is likely to affect your reactions and ability to drive. It is an offence to drive while your reactions are impaired. Even if your driving ability is not impaired, should you drive, you are advised to carry with you some evidence that the medicine has been prescribed for you - a repeat prescription form or a patient information leaflet from the pack is generally considered suitable.

  • If you are due to have an operation, it is important that you tell the person carrying out the treatment that you are taking dexamfetamine.

  • Taking dexamfetamine can lead to your body becoming dependent on it. Your doctor will discuss this with you before you start treatment.

  • Do not stop taking dexamfetamine unless your doctor tells you to do so. This is because stopping it suddenly can cause problems and your doctor is likely to recommend that your dose should be reduced gradually.

Additional information if dexamfetamine is for narcolepsy

  • Have a regular sleep routine. 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 times each day. Some people find that scheduled naps during the day can help to reduce their daytime sleepiness.

  • In the UK, you are required to let the Driver and Vehicle Licensing Authority (DVLA) know if you are diagnosed with narcolepsy. You should stop driving straightaway, and not drive again until you are permitted to do so by the DVLA.

  • You should try to avoid heavy meals, as these can make you sleepy. Doing regular exercise may be of benefit and may help your symptoms.

  • You may find it helpful to tell close friends and work colleagues about your condition. This will help them to understand your symptoms, and there may be help that they can give you, such as help with working schedules.

Additional information if dexamfetamine is for ADHD

  • There are treatment programmes that will be recommended for you and/or your child. These will provide you with strategies to improve behaviour and reduce any long-term impact.

  • From time to time your doctor will assess the treatment to make sure it is still required. This may involve stopping dexamfetamine for a short while.

  • There is a small amount of evidence to show that a change in diet may help some people with ADHD. If you think that diet may be a factor for you or your child, discuss this with your doctor to see if speaking with a dietician might be of benefit.

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Can dexamfetamine cause problems?

Along with their useful effects, all medicines can cause unwanted side-effects although not everyone experiences them. The table below lists some of the most common ones associated with dexamfetamine. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve over the first few days of taking a new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common dexamfetamine side-effects

What can I do if I experience this?

Feeling sick (nausea), stomach cramps

Stick to simple meals - avoid rich or spicy foods

Feeling dizzy, eyesight problems

If this happens, do not drive and do not use tools or machines


Drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If the headaches continue, let your doctor know

Dry mouth, unusual taste

Try chewing sugar-free gum or sucking sugar-free sweets


Drink plenty of water to replace lost fluids

Sleeping problems, mood changes, feeling unsteady or shaky, lack of appetite, loss of weight, a feeling that your heart is pounding (palpitations), hair thinning, itchy rash, sweating, unusual movements, sexual difficulties

Speak with your doctor about any of these

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

How to store dexamfetamine

  • 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 are using the oral solution, you should safely dispose of any remaining liquid once the bottle has been open for 30 days. Make a note of the date when you open the bottle.

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else may have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. 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.

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.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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