Elvanse (lisdexamfetamine) side effects
The most common side effects of Elvanse are difficulty falling asleep, reduced appetite and headaches: each affects more than 1 in 10 people.
Elvanse side effects and what helpsADHD medication side effects
Side effects of ADHD medicines are most noticeable in the first few weeks, and many ease. The stimulants (lisdexamfetamine, dexamfetamine and methylphenidate) very often affect sleep and cause headaches, and often reduce appetite. Atomoxetine often causes nausea and a reduced appetite at first. Guanfacine often causes sleepiness and can lower blood pressure. Choose your medicine for why it causes each side effect, what helps, and when to get help.
Written and clinically reviewed by Adam OdusholaADHD Advanced Practitioner and Clinical Prescribing Pharmacist
Last reviewed: Next review:
Side effects by medicine
Dexamfetamine (Amfexa) side effects
The most common side effects of dexamfetamine (Amfexa) are difficulty falling asleep and reduced appetite: each affects more than 1 in 10 people.
Dexamfetamine side effects and what helpsMethylphenidate IR side effects
The most common side effects of immediate-release methylphenidate are difficulty falling asleep, feeling nervous, headaches and reduced appetite: each affects more than 1 in 10 people.
Methylphenidate IR side effects and what helpsProlonged-release methylphenidate tablet side effects
The most common side effects of prolonged-release methylphenidate tablets such as Concerta XL are difficulty falling asleep, feeling nervous and headaches: each affects more than 1 in 10 people.
Prolonged-release methylphenidate tablets side effects and what helps50:50 modified-release methylphenidate side effects
The most common side effects of 50:50 methylphenidate capsules are difficulty falling asleep, feeling nervous, headaches and reduced appetite: each affects more than 1 in 10 people.
50:50 methylphenidate capsules side effects and what helpsEquasym XL and Tuzulby side effects
The most common side effects of Equasym XL and Tuzulby are difficulty falling asleep, feeling nervous and headaches: each affects more than 1 in 10 people.
Equasym XL and Tuzulby side effects and what helpsAtomoxetine side effects
The most common side effects of atomoxetine are feeling sick, reduced appetite, headaches and a rise in heart rate and blood pressure: each affects more than 1 in 10 people.
Atomoxetine side effects and what helpsGuanfacine side effects
The most common side effects of guanfacine are sleepiness, tiredness, headaches and stomach ache: each affects more than 1 in 10 people.
Guanfacine side effects and what helpsCommon questions about ADHD medication side effects
Is it a side effect, or my medicine wearing off?
Timing is the best clue. A side effect usually shows up while the medicine is working, such as a poor appetite at lunchtime. Wearing off happens as a dose runs out, often late in the day: your usual ADHD symptoms come back, and some people feel more tired, low or irritable for a while. Write down what you feel and when it starts, and take the notes to your review.
Do ADHD medication side effects go away?
Many early side effects, such as headaches, feeling sick and sleepiness on guanfacine, are most noticeable in the first few weeks and often ease. Others, such as a reduced appetite, also tend to settle, but for some people they last for as long as they take the medicine. If a side effect bothers you or does not go away, tell your prescriber: a change of timing, dose or medicine often helps.
What should I note down for my review?
For each side effect: what it is, when it starts in relation to your dose, how long it lasts, how bad it is and what helps. Note your sleep and appetite, and your weight if you can. A short daily or weekly note is enough, and it makes the review quicker and more useful.
Can I change my dose or stop my medicine myself?
Talk to your prescriber first. They may change the timing or dose, or suggest a different medicine. Never stop guanfacine suddenly: it has to be reduced gradually because blood pressure can rise if it is stopped at once.
When should I not wait for my next review?
Call 999 for severe chest pain or chest pain spreading to your arm, jaw or back, severe breathlessness, a seizure, signs of a stroke, a severe allergic reaction, or if you feel you might act on thoughts of harming yourself. Contact your prescriber or 111 today for mild chest pain, a racing heart at rest, new thoughts of self-harm or a new rash. Each medicine’s page lists its own warning signs.
Sources
How common each side effect is comes from the product information (SmPC) for each medicine.
About this page
- Written and clinically reviewed by
- Adam OdusholaADHD Advanced Practitioner and Clinical Prescribing Pharmacist
- First published
- Last updated
- Last reviewed
- Next review
- What changed
- October 2026: common questions and sources added. Advice on when to get help is now on each medicine’s page and matches its guide.
“Last updated” is when the content last changed. “Last reviewed” is when it was last checked against current sources.
How this content is written, sourced and checked: editorial policy
Spotted an error? Report it by email. This is for website feedback only. It can’t give advice about your own treatment.
Info
This guide is for general information only. It does not replace medical advice. Always follow your prescriber or pharmacist. Information is UK-based and aligned with NICE guidelines. © 2026 ADHDnotepad: clinician-authored.