How it works
What does dexamfetamine do?
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.
How long does dexamfetamine take to start working?
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.
How long will I need to take dexamfetamine?
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 ‘holiday’) 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 ‘controlled drug’ 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.
Your doctor needs to know if...
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 ‘E’ numbers.
Some dexamfetamine tablets may contain lactose and isomalt. Check with your pharmacist if these ingredients are a concern for you.
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
- ‘tics’ (movements you cannot control), or Tourette’s 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
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.