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Your guide to medication Dexamfetamine (including lisdexamfetamine)

Dexamfetamine is a central nervous stimulant (CNS) used to treat attention deficit hyperactivity disorder (ADHD).

Medication name: Dexamfetamine ("DEX-am-FET-a-meen")
Brand name: Amfexa ("am-FEX-a")
Medication type: Central nervous stimulant

Ways to take it
Tablets: 5mg, 10mg and 20mg strengths
Capsules*: 20mg, 30mg, 50mg 60mg and 70mg strengths
Liquids: 1mg/ml (one 5ml spoonful of the oral solution is like one 5mg tablet)

*The capsules contain lisdexamfetamine which gets converted slowly to dexamfetamine. This allows you to take it only once a day. Lisdexamfetamine is known as a ‚Äėprodrug‚Äô of dexamfetamine and can be used in adults.

What can it be used for?
A specialist can prescribe dexamfetamine for you as a licensed medicine for treatment of attention deficit hyperactivity disorder (ADHD). This applies to both children and adults.

Dexamfetamine can be used in adults who have narcolepsy, where they fall asleep too easily and without warning, but using it to treat narcolepsy in children is an 'off-label' usage.

 

N.B. Dexamfetamine is a 'controlled drug', meaning there are special rules and laws regarding how it is supplied when prescribed.

ADHD and mental health

About dexamfetamine

Please note

  • This page will give you general information about dexamfetamine. It is not medical advice.

    Always talk to your doctor about your situation and whether this medication is for you.

  • Dexamfetamine is a 'controlled drug'

    This is because it might be sold as a street drug.

    This means that the pharmacy must take special care of the tablets by locking them in a cupboard. The doctor must also write extra things on the prescription, like the total amount needed in words and figures to make it very clear.

    A prescription for dexamfetamine must be dispensed by the pharmacy within 28 days of the prescription being written (you can keep most other prescriptions for six months).

    You cannot get an emergency supply of dexamfetamine without a prescription and if you must take it to school, it might have to be locked in a safe place or special arrangements put in place.

How dexamfetamine works

When used to treat ADHD, dexamfetamine can help to adjust the chemicals your brain needs and focus your energy. It also stimulates centres in the brain that are underactive.

It works on two chemicals called noradrenaline and dopamine. These transmitters carry messages across cells in the brain. Dexamfetamine is a molecule that mimics the action of these two chemicals, acting as a substitute.

Higher levels of noradrenaline and dopamine in the brain help to make people alert and ready for action, feeling like they have more energy and increased wellbeing.

It might seem odd at first that we would use a stimulant as a treatment for hyperactivity, but this seems to give people a better focus for their energy.

With higher levels of noradrenaline and dopamine in the brain, many other effects occur in different parts of the body, including the heart, the gut, and the lungs. Overall, this leads to the good effects of the medicine, but can also produce unwanted side effects.

When used to treat narcolepsy, increased levels of dopamine and noradrenaline help people to stay awake and alert.

ADHD and mental health

Dexamfetamine and everyday life

Frequently asked questions

You should see improvements in your concentration and other symptoms within one month of starting the medicine.

Your doctor might start you on a low dose and then increase it slowly over two to four weeks to your full dose.

You may lose weight while taking dexamfetamine, as it may make you want to eat less.

It is very difficult to know how it will affect each person who takes it.

Dexamfetamine can also affect your growth.

Talk to your doctor before starting this medication if you have concerns about how it might affect your weight and growth.

Your doctor will check your weight and height at least every six months.

If you are not growing as fast as your friends, the doctor may stop the dexamfetamine for a while to let your growth recover.

You may want to let your family and friends know you are taking dexamfetamine so they can support you and help you look out for side effects.

For guidance on this, check out our page on getting support with your medication.

Dexamfetamine can keep you awake, as it is a stimulant. Talk to your doctor about this if it worries you.

The oral solution is likely to be sugar-free but may have some preservatives in it that can cause allergies - talk to your pharmacist if you have problems with food additives or ‚ÄėE‚Äô numbers.

Some dexamfetamine tablets may contain lactose and isomalt. Check with your pharmacist if these ingredients are a concern for you.

Alcohol

If you drink alcohol when you are taking dexamfetamine, it can strengthen the effect of the dexamfetamine, which may give you side effects as if you had taken too much of it.

Your blood pressure and heart rate could also be increased to dangerous levels.

If you decide to drink alcohol, drink only small amounts and see how it affects you. Make sure you are with friends to help you if you need it.

Remember that some foods also contain alcohol.

Street drugs

Dexamfetamine is dangerous to take with cocaine or ecstasy or other amfetamines. This is because they are all stimulants and may together put too much pressure on your heart and the blood vessels in your brain.

Mixing methadone with dexamfetamine can cause serious heart problems and may trigger a dangerous condition known as serotonin syndrome.

Dexamfetamine may add to the pain-killing effects of heroin. You might hurt yourself and not feel enough pain to get help.

Dexamfetamine is also known as a street drug as it‚Äôs a stimulant, so some people use it to get ‚Äėhigh.‚Äô

People taking dexamfetamine from their doctor can be targeted at school and bullied to give away or sell their medicine. If this happens to you, ask your parent, teacher or doctor to help you.

Remember that dexamfetamine has serious side effects. Do not give or sell your tablets to anyone else ‚Äď they may become very ill.

Do not take dexamfetamine if you have taken a monoamine oxidase inhibitor antidepressant (MAOI) like moclobemide, phenelzine, isocarboxazid or tranylcypromine in the last 14 days.

Taking a MAOI with dexamfetamine may cause a sudden and dangerous increase in your blood pressure.

If you are taking other medicines, dexamfetamine may affect how well they work or may cause side effects. Tell your doctor about these before you start your treatment.

Talk to your pharmacist if you buy any medications over the counter to treat common illnesses like colds and flu, or topical applications that you put on your skin.

Taking dexamfetamine may give you blurred vision, make you feel dizzy, make it difficult to concentrate or affect your focus when you start taking it.

It may be best to stop doing things like driving a car, riding a bike, or anything else that needs a lot of focus for the first few days, until you know how it affects you.

Do not worry - most people do these things as normal while taking dexamfetamine.

There is now a ‚Äėdrug driving‚Äô offence where someone driving dangerously, who has taken dexamfetamine, could be arrested.

It is important to stick to the dose on the prescription, and to check that you can drive safely while taking it.

You may also have to prove that you have been given dexamfetamine on prescription, so you could keep your repeat prescription slip or get a letter to explain it from your doctor.

Pregnancy

You should use good contraception when you are taking dexamfetamine.

If you and your partner are trying to have a baby, you should go back to the doctor to discuss your medication options.

We know very little about its effects on a developing baby, but studies suggest amfetamines do not increase the risk of malformations.

Amfetamines have been linked to other pregnancy problems such as anemia, and to an increased risk of still birth.

Post-natal

You may be more likely to need a caesarean section when it is time to have your baby.

If you agree with your doctor to carry on taking dexamfetamine, you should tell your midwife that you are taking it as soon as possible.

Breastfeeding

Dexamfetamine can be passed to the baby in breast milk. Your baby will get about a twentieth of your dose and most sources will say not to breastfeed.

Talk to your doctor or midwife about your feeding options.

Sex

Dexamfetamine can have side effects that might affect your sex life. These include:

  • wanting to have sex less or losing pleasure in having sex
  • difficulty getting an erection (getting hard)

These effects should pass after the first couple of weeks. If they do not, and this is a problem for you, go back to the doctor and see what other treatment you could try.

Fertility

There is nothing to suggest that dexamfetamine affects fertility.

Dexamfetamine is a stimulant, and this makes it a banned substance in sport.

If you play sport to a high level, and want to compete where drug-testing will happen, you will need to go back to your doctor to discuss other ways of managing your ADHD.

Talk to your doctor before starting to take dexamfetamine if you are about to sit any exams or tests, as it can initially make you feel very tired and woozy along with affecting your eyesight. You might decide together to delay starting it until you have completed your exams, or your doctor might suggest some alternative medications.

If your exams are more than a week away, however, you may decide with your doctor that it’s better to start taking dexamfetamine to improve your motivation to study.

Try not to worry ‚Äď most people can take exams and tests as normal while taking dexamfetamine.

Your doctor should know

  • You need to talk to your doctor or pharmacist before starting treatment with dexamfetamine if any of the following apply to you:

    • heart or blood circulation problems
    • ‚Äėtics‚Äô (movements you cannot control), or¬†Tourette‚Äôs syndrome
    • you have ever been¬†dependent¬†in the past on drugs or alcohol
    • thyroid problems
    • unusual feelings of excitement that are not linked to your¬†ADHD
    • increased pressure in your eye (glaucoma)
    • a blood problem called porphyria
    • an allergy to dexamfetamine, other similar medicines like¬†methylphenidate, or any of the other ingredients in the medicines

Uses, warnings, safety and side effects

Taking dexamfetamine

How long will I have to take dexamfetamine for?

Most people take dexamfetamine for at least a year, and then discuss if they need to continue it with their doctor. Stopping before this time might mean your symptoms come back.

You and your doctor should talk about how long you need to take dexamfetamine before you start taking it.

After a year, the doctor may suggest stopping the medicine for a short period (taking a drug ‚Äėholiday‚Äô) to see if you still need it.

You may find you take dexamfetamine for much longer than a year if it is having a positive effect on your ADHD.

Dexamfetamine is prescribed as part of a wider treatment plan for ADHD. This plan may include educational, social and psychological counselling.

Dexamfetamine is a ‚Äėcontrolled drug‚Äô because it might be sold as a street drug.

This means that the pharmacy must take special care of the tablets by locking them in a cupboard. The doctor must also write extra things on the prescription, like the total amount needed in words and figures to make it very clear.

A prescription for dexamfetamine must be dispensed by the pharmacy within 28 days of the prescription being written (you can keep most other prescriptions for six months).

You cannot get an emergency supply of dexampfetamine without a prescription and if you must take it to school, it might have to be locked in a safe place or special arrangements put in place.

You should only take dexamfetamine as agreed with your doctor

You might have to take plain dexamfetamine (as opposed to lisdexamfetamine) up to four times a day.

You will get the best effect from your dexamfetamine if you take it every day at the dose prescribed by your doctor.

Make sure that you know your dose. If it is not written on the label, check with your pharmacist or doctor.

You can take dexamfetamine with or without food.

If you need to break a tablet to get your exact dose, please ask the pharmacist how to do this accurately. The capsules of lisdexamfetamine should be swallowed whole and not chewed.

What if I miss a dose?

Once you remember, take it as soon as possible.

If you do not remember to take it before the next dose, just leave it and take the next dose.

Do not take a double dose.

What will happen if I forget to take my dexamfetamine?

If you forget to take it for a few days, your symptoms may come back.

You may get an unwanted effect of feeling very low as the chemicals in your brain change their balance, with less noradrenaline and dopamine around.

You may also feel very tired.

Stopping the use of dexamfetamine

Stopping this medicine quickly, or reducing the dose too much at once, may cause uncomfortable withdrawal symptoms.

You can stop taking dexamfetamine safely and gradually with your doctor’s help.

Your ADHD symptoms could return, or the sudden drop in noradrenaline and dopamine in your brain could bring on symptoms of depression and extreme tiredness.

Go and speak to your doctor if you have missed a few doses or have decided to stop taking your medication.

Withdrawal symptoms should stop after a few days. If they do not, or they are stopping you getting on with your life, you might need the help of a doctor.

Warnings and safety

Safety headlines

If you have taken more dexamfetamine than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately ‚Ästeven if you do not feel any different.

Dexamfetamine can cause serious side effects: allergic reactions (high body temperature, swelling of your face or throat, itching skin lumps), twitching and other symptoms that can be found here. Go to a hospital if you get any of these symptoms, taking your medicine with you.  

Do not take dexamfetamine if you have taken a monoamine oxidase inhibitor antidepressant (MAOI) like moclobemide, phenelzine, isocarboxazid or tranylcypromine in the last 14 days.

Stopping dexamfetamine suddenly can cause serious side effects. Go to your doctor if you want to stop, or if you are having these effects.

You might feel sleepy or have problems with your eyesight in the first few days after taking dexamfetamine. Do not drive a car, ride a bike or operate machines until you see how this affects you.

We do not know how safe dexamfetamine is in pregnancy. Use good contraception while you are taking dexamfetamine. See your doctor to get advice if you become pregnant, but there is no urgent need to stop dexamfetamine.

Dexamfetamine is passed in small amounts to the baby in breast milk. Talk to your doctor or midwife about this and get their help.

When to go to the hospital

If you have taken more dexamfetamine than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately ‚Ästeven if you do not feel any different.

Go to A&E. Take your medicine with you to show to the doctors. Tell them how much you have taken.

Get a friend or family member to go with you if you can, just in case you feel ill on the way.

You might get any of the following signs:

  • feeling very excited
  • having a seizure (fit), which can lead to a coma
  • hallucinating (seeing, feeling or hearing things that are not real)
  • changes in your heartbeat (slow, fast or uneven)
  • your breathing getting slower

When to see your doctor

You need to see a doctor straight away if you get any of the following side effects: 

  • high body temperature
  • twitching
  • sudden wheeziness and tightness in your chest
  • swelling of your eyelids, face, lips or throat
  • skin lumps or ‚Äėhives‚Äô
  • a red spotty skin rash that is itchy
  • collapsing

Monitoring

Before you start taking dexamfetamine, if you change your dose, and at least every six months after you start, the doctor will do some tests to check that dexamfetamine is (still) right for you.

They will check your appetite, as dexamfetamine can make you want to eat less.        

They will check your weight and height, as dexamfetamine can slow down your growth.

They will check your heart rate and blood pressure, as this is a stimulant that can have side effects on the heart and blood vessels.

They will ask you about your mood and how you are feeling to check that the medicine is working, but also whether you are having any side effects.

They will ask you about any feelings of aggression or dislike towards others, which can be a side effect of the medicine.

Side effects

Side effects

Very common side effects of taking dexamfetamine (affecting more than one in ten people) include:

  • disturbed sleep
  • feeling anxious or nervous
  • decreased appetite leading to lack of normal weight gain and, possibly, weight loss

Common side effects of taking dexamfetamine (affecting up to one in ten people) include:

  • feeling unusually happy
  • feeling irritable or aggressive
  • feeling confused or having a low mood (depression)
  • cramps or pain in your gut
  • feeling sick
  • dry mouth and changes in how you taste things
  • heart and blood pressure changes, including fast heart rate
  • rashes or itching skin
  • muscle pain

There are other side effects that you can get when taking this medicine. We have only included the most common ones here.

Some side effects that appear should get better after a few days. If they do not, you should go back to your doctor.

Please look at the leaflet inside your medicine box, or ask a doctor or pharmacist, if you want to know whether you are getting a side effect from your medicine. 

If you do get a side effect, please think about reporting it via the 'Yellow Card' scheme.

Taking dexamfetamine

How long will I have to take dexamfetamine for?

Most people take dexamfetamine for at least a year, and then discuss if they need to continue it with their doctor. Stopping before this time might mean your symptoms come back.

You and your doctor should talk about how long you need to take dexamfetamine before you start taking it.

After a year, the doctor may suggest stopping the medicine for a short period (taking a drug ‚Äėholiday‚Äô) to see if you still need it.

You may find you take dexamfetamine for much longer than a year if it is having a positive effect on your ADHD.

Dexamfetamine is prescribed as part of a wider treatment plan for ADHD. This plan may include educational, social and psychological counselling.

Dexamfetamine is a ‚Äėcontrolled drug‚Äô because it might be sold as a street drug.

This means that the pharmacy must take special care of the tablets by locking them in a cupboard. The doctor must also write extra things on the prescription, like the total amount needed in words and figures to make it very clear.

A prescription for dexamfetamine must be dispensed by the pharmacy within 28 days of the prescription being written (you can keep most other prescriptions for six months).

You cannot get an emergency supply of dexampfetamine without a prescription and if you must take it to school, it might have to be locked in a safe place or special arrangements put in place.

You should only take dexamfetamine as agreed with your doctor

You might have to take plain dexamfetamine (as opposed to lisdexamfetamine) up to four times a day.

You will get the best effect from your dexamfetamine if you take it every day at the dose prescribed by your doctor.

Make sure that you know your dose. If it is not written on the label, check with your pharmacist or doctor.

You can take dexamfetamine with or without food.

If you need to break a tablet to get your exact dose, please ask the pharmacist how to do this accurately. The capsules of lisdexamfetamine should be swallowed whole and not chewed.

What if I miss a dose?

Once you remember, take it as soon as possible.

If you do not remember to take it before the next dose, just leave it and take the next dose.

Do not take a double dose.

What will happen if I forget to take my dexamfetamine?

If you forget to take it for a few days, your symptoms may come back.

You may get an unwanted effect of feeling very low as the chemicals in your brain change their balance, with less noradrenaline and dopamine around.

You may also feel very tired.

Stopping the use of dexamfetamine

Stopping this medicine quickly, or reducing the dose too much at once, may cause uncomfortable withdrawal symptoms.

You can stop taking dexamfetamine safely and gradually with your doctor’s help.

Your ADHD symptoms could return, or the sudden drop in noradrenaline and dopamine in your brain could bring on symptoms of depression and extreme tiredness.

Go and speak to your doctor if you have missed a few doses or have decided to stop taking your medication.

Withdrawal symptoms should stop after a few days. If they do not, or they are stopping you getting on with your life, you might need the help of a doctor.

Warnings and safety

Safety headlines

If you have taken more dexamfetamine than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately ‚Ästeven if you do not feel any different.

Dexamfetamine can cause serious side effects: allergic reactions (high body temperature, swelling of your face or throat, itching skin lumps), twitching and other symptoms that can be found here. Go to a hospital if you get any of these symptoms, taking your medicine with you.  

Do not take dexamfetamine if you have taken a monoamine oxidase inhibitor antidepressant (MAOI) like moclobemide, phenelzine, isocarboxazid or tranylcypromine in the last 14 days.

Stopping dexamfetamine suddenly can cause serious side effects. Go to your doctor if you want to stop, or if you are having these effects.

You might feel sleepy or have problems with your eyesight in the first few days after taking dexamfetamine. Do not drive a car, ride a bike or operate machines until you see how this affects you.

We do not know how safe dexamfetamine is in pregnancy. Use good contraception while you are taking dexamfetamine. See your doctor to get advice if you become pregnant, but there is no urgent need to stop dexamfetamine.

Dexamfetamine is passed in small amounts to the baby in breast milk. Talk to your doctor or midwife about this and get their help.

When to go to the hospital

If you have taken more dexamfetamine than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately ‚Ästeven if you do not feel any different.

Go to A&E. Take your medicine with you to show to the doctors. Tell them how much you have taken.

Get a friend or family member to go with you if you can, just in case you feel ill on the way.

You might get any of the following signs:

  • feeling very excited
  • having a seizure (fit), which can lead to a coma
  • hallucinating (seeing, feeling or hearing things that are not real)
  • changes in your heartbeat (slow, fast or uneven)
  • your breathing getting slower

When to see your doctor

You need to see a doctor straight away if you get any of the following side effects: 

  • high body temperature
  • twitching
  • sudden wheeziness and tightness in your chest
  • swelling of your eyelids, face, lips or throat
  • skin lumps or ‚Äėhives‚Äô
  • a red spotty skin rash that is itchy
  • collapsing

Monitoring

Before you start taking dexamfetamine, if you change your dose, and at least every six months after you start, the doctor will do some tests to check that dexamfetamine is (still) right for you.

They will check your appetite, as dexamfetamine can make you want to eat less.        

They will check your weight and height, as dexamfetamine can slow down your growth.

They will check your heart rate and blood pressure, as this is a stimulant that can have side effects on the heart and blood vessels.

They will ask you about your mood and how you are feeling to check that the medicine is working, but also whether you are having any side effects.

They will ask you about any feelings of aggression or dislike towards others, which can be a side effect of the medicine.

Side effects

Side effects

Very common side effects of taking dexamfetamine (affecting more than one in ten people) include:

  • disturbed sleep
  • feeling anxious or nervous
  • decreased appetite leading to lack of normal weight gain and, possibly, weight loss

Common side effects of taking dexamfetamine (affecting up to one in ten people) include:

  • feeling unusually happy
  • feeling irritable or aggressive
  • feeling confused or having a low mood (depression)
  • cramps or pain in your gut
  • feeling sick
  • dry mouth and changes in how you taste things
  • heart and blood pressure changes, including fast heart rate
  • rashes or itching skin
  • muscle pain

There are other side effects that you can get when taking this medicine. We have only included the most common ones here.

Some side effects that appear should get better after a few days. If they do not, you should go back to your doctor.

Please look at the leaflet inside your medicine box, or ask a doctor or pharmacist, if you want to know whether you are getting a side effect from your medicine. 

If you do get a side effect, please think about reporting it via the 'Yellow Card' scheme.

About this information

The information on this page was reviewed by the College of Mental Health Pharmacy in March 2020.

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