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Dexamfetamine for narcolepsy and ADHD

Amfexa

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

Tipo de medicamento

Un estimulante

Utilizado para

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

Also known as (UK)

Amfexa®

Also known as (USA)

Dextroamphetamine; Dexedrine®, Adderall®

Disponible como

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:

  • Si está embarazada, esperando un bebé o en período de lactancia.

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

  • Si tiene algún problema con el funcionamiento de sus riñones.

  • Si tiene una glándula tiroides hiperactiva (hipertiroidismo).

  • Si tiene la tensión alta.

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

  • Si padece epilepsia.

  • 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.

  • Si padece una rara enfermedad hereditaria de la sangre llamada porfiria.

  • Si está tomando otros medicamentos. Esto incluye todos los medicamentos que se pueden comprar sin receta, así como las hierbas medicinales y los medicamentos complementarios.

  • Si alguna vez ha tenido una reacción alérgica a un medicamento.

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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.

Aproveche al máximo su tratamiento

  • 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

¿Qué puedo hacer si me ocurre esto?

Feeling sick (nausea), stomach cramps

Comidas sencillas: evite los alimentos ricos o picantes.

Sensación de mareo, problemas de visión

Si esto ocurre, no conduzca ni utilice herramientas o máquinas.

Dolor de cabeza

Bebe mucha agua y pide a tu farmacéutico que te recomiende un analgésico adecuado. Si los dolores de cabeza persisten, informe a su médico.

Dry mouth, unusual taste

Prueba a mascar chicle sin azúcar o chupar caramelos sin azúcar

Diarrea

Beber mucha agua para reponer los líquidos perdidos

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

Si experimenta cualquier otro síntoma que considere que puede deberse a este medicamento, consulte a su médico o farmacéutico.

How to store dexamfetamine

  • Mantenga todos los medicamentos fuera del alcance y de la vista de los niños.

  • Almacenar en un lugar fresco y seco, lejos del calor y la luz directos.

  • 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.

Información importante sobre todos los medicamentos

Información importante sobre todos los medicamentos

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.

Este medicamento es para usted. Nunca se lo dé a otras personas aunque su enfermedad parezca ser la misma que la suya.

No guarde medicamentos caducados o que no desee. Llévelos a su farmacia local, que se encargará de eliminarlos por usted.

Si tiene cualquier duda sobre este medicamento pregunte a su farmacéutico.

Informar de los efectos secundarios de un medicamento o vacuna

Si experimenta efectos secundarios, puede notificarlos en línea a través del sitio web de la Tarjeta Amarilla.

Lecturas complementarias y referencias

Historia del artículo

La información de esta página ha sido redactada y revisada por médicos cualificados.

  • Fecha límite de la próxima revisión: 8 nov 2025
  • 9 Nov 2022 | Última versión

    Última actualización

    Michael Stewart, MRPharmS

    Revisado por expertos

    Sid Dajani
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