Elvanse (Lisdexamfetamine) Side Effects: What Is Common, What to Watch For and When to Get Help
The first days on a new medicine can make you notice every small change. Is the dry mouth normal? Why has lunch stopped feeling important? Is a racing heart a side effect, or nerves? If you are a parent, you are also trying to read signs that a child may not mention.
This guide sets out the side effects listed in the official UK product information for Elvanse, split by age group, and marks the ones that need a call to your prescriber or urgent help. It is here to help you have a better conversation with your prescriber, not to replace one.
What are the side effects of Elvanse? The UK product information lists decreased appetite, difficulty sleeping and headache as very common (more than 1 in 10 people) in children, teenagers and adults. Dry mouth is also very common in adults, upper stomach pain in children, and weight loss in children and teenagers. Raised heart rate, anxiety, irritability and mood changes are common. Get urgent help for chest pain, an uneven heartbeat, seeing or hearing things that are not real, a seizure, swelling of the skin, or a severe skin reaction. Your prescriber should check blood pressure, pulse, mood and (for children) height, weight and appetite when the dose changes and at least every 6 months.
Your prescriber assesses you, diagnoses ADHD, chooses your medicine and dose, and monitors your treatment. Pharmazon HomeCare checks, dispenses and delivers a valid prescription. We do not assess, diagnose or prescribe. For an overview of how Elvanse works and who it is licensed for, read our full Elvanse guide.
Very common side effects
Elvanse is a stimulant. Your body converts lisdexamfetamine into dexamfetamine, which acts on the brain's noradrenaline and dopamine systems. That helps explain why appetite, sleep and heart rate can be affected.
The Summary of Product Characteristics (SmPC) gives side effect frequencies separately for children (6 to 12), adolescents (13 to 17) and adults. "Very common" means more than 1 in 10 people.
| Side effect | Children | Teenagers | Adults |
|---|---|---|---|
| Decreased appetite | Very common | Very common | Very common |
| Difficulty sleeping (insomnia) | Very common | Very common | Very common |
| Headache | Very common | Very common | Very common |
| Dry mouth | Common | Common | Very common |
| Upper stomach pain | Very common | Common | Common |
| Weight loss | Very common | Very common | Common |
Common side effects by age group
Common means up to 1 in 10 people. The lists below are the common effects the SmPC reports for each age group, in addition to the very common ones above.
| Age group | Common side effects listed in the SmPC |
|---|---|
| Children (6 to 12) | Tics, mood swings, aggression, dizziness, sleepiness, fast heart rate, dry mouth, diarrhoea, constipation, nausea, vomiting, rash, irritability, tiredness, fever |
| Teenagers (13 to 17) | Anxiety, low mood (depression), dizziness, restlessness, tremor, sleepiness, fast heart rate, palpitations, shortness of breath, dry mouth, diarrhoea, upper stomach pain, nausea, vomiting, irritability, tiredness, feeling jittery, fever |
| Adults | Agitation, anxiety, reduced sex drive, mood swings, overactivity, teeth grinding, dizziness, restlessness, tremor, fast heart rate, palpitations, shortness of breath, diarrhoea, constipation, upper stomach pain, nausea, excess sweating, erectile dysfunction, chest pain, irritability, tiredness, feeling jittery, raised blood pressure, weight loss |
Children
Appetite and growth matter most. The SmPC says stimulants have been associated with a slowing of weight gain and a reduction in attained height in children and adolescents. Height, weight and appetite should be recorded at least every 6 months, and treatment may need to be interrupted if a child is not growing or gaining weight as expected. The SmPC also says children should be evaluated for tics before starting a stimulant, so tell the prescriber about any tics, now or in the family.
Teenagers
Mood deserves attention. Low mood, anxiety and irritability are all listed as common. The SmPC also notes that the risk of misuse may be greater in adults, especially young adults, than in children, which is worth keeping in mind for older teenagers who manage their own medicine.
Adults
The SmPC says stimulants cause a modest increase in average blood pressure (about 2 to 4 mmHg) and heart rate (about 3 to 6 beats per minute), and some people have larger increases. That is why blood pressure and pulse are checked regularly. The SmPC also says weight should be recorded regularly in adults, and that people who are losing weight may need their treatment interrupted.
When to seek help
The urgent list below, and the advice on mood and heart problems, come from the Patient Information Leaflet (PIL). The other groupings are practical guidance. If you are unsure which group a symptom belongs in, ask your prescriber or a pharmacist.
Mention at your next review, if mild
- Dry mouth
- Headache
- Mild stomach ache
- Mild jitteriness
The PIL says that if these effects get serious, you should tell your doctor or pharmacist.
Tell your prescriber soon
- Appetite loss with ongoing weight loss
- Sleep that is not settling
- Tics that are new or more frequent
- Any change in mood or how you feel. The PIL says to talk to your doctor straight away about this
- A fast or racing heartbeat at rest. The PIL says to tell your doctor straight away about any heart problems
- Blurred vision or trouble focusing
Get urgent medical help (see a doctor straight away, or call 999 in an emergency) for:
- Chest pain or an uneven heartbeat (palpitations)
- Feeling unusually excited, over-active or uninhibited (mania)
- Seeing, feeling or hearing things that are not real, paranoia or delusions
- Worsening tics
- A seizure (fit)
- An allergic reaction, swelling of the skin, or a serious skin rash with blisters
- Breathlessness or swelling of the legs
- Yellowing of the eyes or skin
If you or your child have thoughts of harming yourselves, get help straight away: speak to your prescriber, call NHS 111 or call 999.
Practical points for taking Elvanse
Talk to your prescriber before changing how or when you take Elvanse.
- Take it in the morning. The PIL says to avoid taking it in the afternoon because of the possibility of sleep disturbances. In clinical studies, effects were still present 13 hours after dosing in children and 14 hours in adults.
- With or without food. The SmPC says Elvanse may be taken with or without food.
- Keep a short diary. Note sleep, meals, mood and any symptoms for the first few weeks. It makes reviews more useful.
- Ask about appetite and dry mouth. Your pharmacist can suggest practical ways to manage both.
- Check before taking other medicines. The SmPC says Elvanse must not be used with monoamine oxidase inhibitors (MAOIs) or within 14 days after stopping one. It also says serotonin syndrome has rarely occurred when amfetamines are given with serotonergic medicines, including SSRI and SNRI antidepressants. Vitamin C (ascorbic acid) and some other agents that acidify the urine increase how quickly the body clears amfetamine, and sodium bicarbonate and agents that make urine more alkaline do the opposite. Ask a pharmacist before you start anything new.
- Do not drive until you know how it affects you. The PIL says Elvanse can make you sleepy or dizzy, or cause problems focusing or blurred vision. See Elvanse controlled drug rules for the driving law.
If side effects are hard to live with, your prescriber may change your dose. See Elvanse doses and strengths and what happens if ADHD medication stops working.
What your prescriber should check
| What is checked | How often, according to the product information |
|---|---|
| Blood pressure and pulse | At each dose adjustment and at least every 6 months |
| Height, weight and appetite (children and teenagers) | At least every 6 months |
| Weight (adults) | Regularly |
| Mood and mental state | At each dose adjustment, then at least every 6 months and at every visit |
| Review of whether Elvanse is still helping | At least yearly if used for more than 12 months. Trial periods off medication may be considered |
Before you start, your prescriber should also ask about heart conditions, mental health history and family history, including any family history of sudden cardiac or unexplained death.
Serious risks listed in the product information
These are not common, but your prescriber considers them before and during treatment:
- Heart: sudden death has been reported in children and adolescents with structural heart abnormalities or other serious heart problems. In adults, sudden death, stroke and heart attack have been reported with stimulants at usual doses.
- Mental health: stimulants can cause psychotic or manic symptoms, and aggressive behaviour or hostility has been reported.
- Seizures: stimulants may lower the convulsive threshold in some people.
- Misuse and dependence: Elvanse has a potential for abuse, misuse, dependence or diversion.
The SmPC lists some conditions where Elvanse must not be used, including symptomatic cardiovascular disease, moderate to severe high blood pressure, glaucoma, an overactive thyroid and agitated states. Tell your prescriber about any heart condition, high blood pressure, mental health history, seizures, tics or Tourette's, and any medicines or supplements you take.
Reporting a side effect: the Yellow Card scheme
You can report any suspected side effect to the MHRA through the Yellow Card scheme. Patients, parents and carers can report, not only healthcare professionals. Reports help the MHRA monitor the safety of medicines in the UK.
Getting your Elvanse prescription dispensed
Pharmazon HomeCare is a GPhC-registered pharmacy in the Harley Street Medical Area, part of the Excelsior Health group. We dispense valid prescriptions from GPs, psychiatrists and private ADHD clinics. We do not assess, diagnose or prescribe. Our pharmacists can talk through side effects, interactions and timing with you, and point you back to your prescriber when a change is needed. Find out more about Elvanse prescription delivery.
Why Pharmazon HomeCare: every prescription is checked by a GPhC-registered pharmacist before anything is dispensed, and medicines are sent by tracked, signed-for delivery in discreet packaging. Delivery options depend on the order, and we cannot guarantee stock of any strength. Get in touch with our pharmacy team. Clinics and prescribers: Become a clinic partner.
For the full process of how prescriptions reach us, see How a private Elvanse prescription works.
Related guides
- Elvanse doses and strengths
- How long Elvanse lasts
- How a private Elvanse prescription works
- Is Elvanse a controlled drug?
- Elvanse and alcohol
- Elvanse vs Vyvanse
- Elvanse (lisdexamfetamine) for ADHD: full guide
- Elvanse prescription delivery
- ADHD medication UK: prescriptions, dispensing and delivery
- ADHD medication FAQs
Frequently asked questions
What are the most common Elvanse side effects?
Decreased appetite, difficulty sleeping and headache are very common in children, teenagers and adults, according to the SmPC. Dry mouth is also very common in adults, upper stomach pain in children, and weight loss in children and teenagers.
Are Elvanse side effects different in children and adults?
Yes. Tics, rash, fever and sleepiness are listed as common in children, and anxiety and low mood in teenagers. Teeth grinding, excess sweating, chest pain and raised blood pressure are listed as common in adults. Mood changes and irritability appear in all age groups.
Does Elvanse affect a child's growth?
The SmPC says stimulants have been associated with a slowing of weight gain and a reduction in attained height in children and adolescents. Height, weight and appetite should be recorded at least every 6 months.
Can Elvanse raise blood pressure and heart rate?
Yes. The SmPC says stimulants cause a modest increase in average blood pressure (about 2 to 4 mmHg) and heart rate (about 3 to 6 beats per minute), and some people have larger increases. Your prescriber should check both regularly.
Can Elvanse cause anxiety or low mood?
Anxiety and irritability are common, and mood swings are common in children and adults. Low mood is listed as common in teenagers. The leaflet says to talk to your doctor straight away if your mood or how you feel changes.
Why can't I sleep on Elvanse?
Difficulty sleeping is very common. The leaflet advises avoiding doses in the afternoon because of the possibility of sleep disturbances. Talk to your prescriber if poor sleep continues, rather than moving your dose yourself.
Which Elvanse side effects need urgent help?
The leaflet says to see a doctor straight away for chest pain, an uneven heartbeat, mania, seeing or hearing things that are not real, worsening tics, seizures, severe allergic or skin reactions, and breathlessness or swelling of the legs.
Can Elvanse affect my eyesight?
The SmPC says difficulties with accommodation and blurred vision have been reported with stimulants. Tell your prescriber if you notice changes in your vision.
Can I drive if I take Elvanse?
Elvanse can make you sleepy or dizzy, or cause blurred vision. Do not drive until you know how it affects you. GOV.UK says you can drive on prescribed amphetamine-type medicines if you follow your healthcare professional's advice and they do not make you unfit to drive.
What should I do if I take too much Elvanse?
The leaflet says to talk to a doctor or call an ambulance straight away, and to tell them how much you have taken.
How do I report an Elvanse side effect?
Through the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk. Patients, parents and carers can all report.
Can a pharmacist help with Elvanse side effects?
Yes. A pharmacist can talk through side effects and interactions with other medicines. Pharmazon HomeCare's pharmacists can advise, and will point you to your prescriber when a dose change may be needed.
References
- Elvanse 30mg Hard Capsules, Summary of Product Characteristics. Takeda UK Ltd. emc, text revised 2 October 2026. Accessed 6 November 2026. https://www.medicines.org.uk/emc/product/14089/smpc
- Elvanse Hard Capsules, Patient Information Leaflet. Takeda UK Ltd. emc, revised October 2026. Accessed 6 November 2026. https://www.medicines.org.uk/emc/product/14089/pil
- MHRA Yellow Card scheme. https://yellowcard.mhra.gov.uk
- GOV.UK. Drugs and driving: the law. Accessed 6 November 2026. https://www.gov.uk/drug-driving-law
About this page. This page is general information based on the sources listed above. It does not replace advice from your prescriber or pharmacist, and it is not medical advice. Pharmazon HomeCare is a dispensing pharmacy. Decisions about your ADHD medicine, dose and monitoring are made by your prescriber. Product information and guidance can change, so always read the Patient Information Leaflet that comes with your medicine.
Pharmazon HomeCare. GPhC-registered pharmacy: 9011805. Superintendent Pharmacist: Mohammed Abou Daya (GPhC: 2083143).