Guide ยท ADHD medication
Lisdexamfetamine (Vyvanse): how it works, what it does and the risks
Lisdexamfetamine (Vyvanse) is a long-acting stimulant used for ADHD, and in adults for binge eating disorder. This guide covers how it works, what the evidence shows, its side effects and controls, and how it compares with dexamfetamine.
Updated 25 September 2026 · About 8 minutes to read · All guides
In short
- Lisdexamfetamine (Vyvanse) is an inactive prodrug that the body converts into dexamfetamine, which is what acts on the brain.
- In Australia it is registered for ADHD (not for children under 6) and for moderate to severe binge eating disorder in adults when non-drug treatment hasn't worked or isn't available.
- It is taken once a day in the morning; in trials, effects were measured from 1.5 to 13 hours after a dose in children and at 14 hours in adults.
- Common side effects include reduced appetite, dry mouth, headache, trouble sleeping and irritability, with small average rises in heart rate and blood pressure.
- It is a Schedule 8 controlled drug; giving or taking someone else's prescription is illegal, and studies in people without ADHD find little or no improvement in thinking.
What lisdexamfetamine is and what it's approved for
Lisdexamfetamine is a stimulant medicine sold in Australia as Vyvanse capsules. It is a prodrug: inactive as swallowed, then converted in the blood, mainly by red blood cells, into dexamfetamine (also spelled dexamphetamine), which is the active medicine.
The TGA-approved product information lists two uses:
- ADHD. It shouldn't be used in children under 6, where it hasn't been studied, and its safety and efficacy haven't been established in people over 55. Treatment is started by a specialist.
- Moderate to severe binge eating disorder in adults, when non-drug treatment hasn't worked or isn't available. For this use it is started by a psychiatrist. The product information states it is not for weight loss.
It is a Schedule 8 controlled drug. The consumer medicine information, a plain-language leaflet, is linked from Healthdirect's Vyvanse page. For how it fits with other options, see our guide to ADHD medication.
How the prodrug design affects onset and duration
Because lisdexamfetamine has to be converted before it works, dexamfetamine levels rise gradually. The product information gives about 3.5 hours as the time to peak dexamfetamine levels in children aged 6 to 12.
In a laboratory-school trial of 129 children aged 6 to 12, effects on attention and behaviour were measurable from the first check, 1.5 hours after a morning dose, through to the last at 13 hours. The product information reports effects at 14 hours in adults. For everyday use, Australian Prescriber gives a duration of about 6 to 12 hours, longer than dexamfetamine tablets.
That long action is why it's taken once a day, in the morning. The product information advises against afternoon doses because they can cause trouble sleeping.
What the evidence shows
- Children and teenagers. A 7-week European trial randomised 336 young people aged 6 to 17 to lisdexamfetamine, long-acting methylphenidate or placebo. Both medicines reduced ADHD symptom scores substantially more than placebo. 196 of the 336 completed it.
- Adults. In the main 4-week adult trial described in the product information (420 adults), all three doses tested improved ADHD rating scale scores more than placebo.
- When it's stopped. In trials where people already taking lisdexamfetamine were randomly kept on it or switched to placebo, without knowing which, symptoms returned far more often on placebo: treatment failure in 67.5% of children and teenagers on placebo versus 15.8% who stayed on lisdexamfetamine, over 6 weeks. The pattern was similar in adults. The benefit lasts while it is taken.
A 2018 network meta-analysis of 133 trials grouped lisdexamfetamine with other amphetamines. At around 12 weeks, amphetamines had the largest average effect on clinician-rated symptoms in both children and adults, but more people stopped them than placebo because of side effects. The Australian ADHD guideline lists lisdexamfetamine, dexamfetamine and methylphenidate together as first-line options and does not rank one above the others. Most of this evidence comes from trials lasting weeks to months.
For binge eating disorder, two 12-week trials in 724 adults found lisdexamfetamine reduced binge days per week more than placebo (about 3.9 fewer binge days a week, against about 2.3 to 2.5 on placebo).
Side effects and who shouldn't take it
Common side effects
In short adult ADHD trials, the most common side effects were reduced appetite (about 1 in 4 people), dry mouth (about 1 in 5), headache (about 1 in 5), trouble sleeping (about 1 in 6) and irritability. In the children's laboratory-school trial, during dose adjustment, 47% had reduced appetite, 27% trouble sleeping, 17% headache and 16% irritability.
Heart, growth and mood
Stimulants raise average blood pressure by about 2 to 4 mmHg and heart rate by about 3 to 6 beats per minute, so both are checked before and during treatment. Slowed growth in weight or height has been reported in children on long-term stimulants. Mood changes, including depression, can occur, and rarely psychotic or manic symptoms at usual doses.
Serious side effects listed in the consumer information include chest pain, shortness of breath, seizures, allergic reactions and suicidal thoughts.
Who shouldn't take it
The product information says it shouldn't be used by people with:
- heart disease causing symptoms, advanced hardening of the arteries, or moderate to severe high blood pressure
- an overactive thyroid or glaucoma
- tics or Tourette syndrome, agitation, severe depression, suicidal thoughts, psychotic symptoms or anorexia nervosa
- drug or alcohol dependence
- an MAOI antidepressant taken in the past 14 days
The product information also lists a few rarer conditions.
In pregnancy it is used only if the benefit justifies the risk, and breastfeeding is advised against.
Misuse, and taking Vyvanse without ADHD
Being a prodrug doesn't remove the risk of misuse. The product information warns that lisdexamfetamine has potential for abuse, misuse, dependence and diversion, and asks prescribers to assess that risk before prescribing. Australian Prescriber notes that misuse and diversion of ADHD stimulants are common.
Taking someone else's Vyvanse is unsafe and illegal. Schedule 8 medicines are prescribed for one person based on their own health, and it is illegal to give or sell them to anyone else. Higher doses of stimulants can raise body temperature and cause seizures, coma and death.
Research on stimulants in people without ADHD doesn't support the 'study drug' reputation:
- A 2020 series of meta-analyses (47 studies of healthy adults) found dexamfetamine, the medicine lisdexamfetamine turns into, had no significant effect on thinking tests. Methylphenidate had small effects in some areas.
- In a trial of 46 healthy young adults, an amphetamine medicine didn't improve performance on 13 cognitive measures overall, yet participants believed it had.
Lisdexamfetamine and dexamfetamine compared
Both end up as the same active medicine, dexamfetamine, so the differences are mostly about timing and how the day is covered.
| Feature | Lisdexamfetamine (Vyvanse) | Dexamfetamine |
|---|---|---|
| What acts in the body | Dexamfetamine, after conversion in the blood | Dexamfetamine, directly |
| Form and dosing | Capsule, once a day in the morning | Tablet, taken one to three times a day |
| How long a dose lasts | About 6 to 12 hours | About 4 to 6 hours |
| TGA-registered uses | ADHD (not under 6); binge eating disorder in adults | ADHD in children (not under 3); narcolepsy |
| Australian guideline | First-line option for children 6 and over, teenagers and adults | First-line option for children 6 and over, teenagers and adults |
| Controls | Schedule 8; potential for misuse | Schedule 8; potential for misuse |
A once-daily capsule avoids a school or work-time dose. Shorter-acting tablets can be timed to cover particular parts of the day and wear off sooner. Stimulants work differently in different people, so one may suit a person better than the other. Our dexamfetamine guide covers it in more detail.
Questions to ask the prescriber
- Why lisdexamfetamine rather than another stimulant or a non-stimulant?
- What time should it be taken, and what should we do about a missed dose?
- Which side effects are expected, and which mean we should contact you?
- How will heart rate, blood pressure, appetite, sleep and growth be monitored?
- How will we judge whether it is working, and when is the next review?
- Does it interact with other medicines or alcohol?
- How should it be stored, and what are the rules for scripts where we live?
This guide is general information, not medical advice. Decisions about starting, changing or stopping lisdexamfetamine are made with the prescribing doctor.
Questions people ask
What is Vyvanse used for?
In Australia, Vyvanse (lisdexamfetamine) is registered for ADHD and for moderate to severe binge eating disorder in adults when non-drug treatment hasn't worked or isn't available. It shouldn't be used in children under 6. It is not approved for weight loss.
How long does Vyvanse last?
Australian Prescriber gives about 6 to 12 hours. In trials, effects were measurable from 1.5 hours to 13 hours after a morning dose in children, and at 14 hours in adults. It is taken once in the morning because afternoon doses can disturb sleep.
What are the side effects of Vyvanse?
The most common are reduced appetite, dry mouth, headache, trouble sleeping and irritability. It also raises average heart rate and blood pressure slightly, and can slow growth in children. Less common but serious effects include chest pain, seizures, mood changes and, rarely, psychotic symptoms.
Vyvanse vs dexamphetamine: what's the difference?
Vyvanse is converted into dexamfetamine in the body, so both end up as the same active medicine. Vyvanse is a once-daily capsule lasting about 6 to 12 hours; dexamfetamine tablets last about 4 to 6 hours and are taken one to three times a day. The Australian guideline lists both as first-line options for ADHD without ranking one above the other.
What happens if you take Vyvanse without ADHD?
You get the same side effects and heart risks as anyone else, without the checks a prescriber would do first, and taking someone else's Schedule 8 medicine is illegal. Studies in healthy adults find stimulants, including dexamfetamine (what Vyvanse becomes), have little or no measurable effect on thinking, even though people may feel sharper.
Related
ADHD medication · Dexamphetamine · Ritalin and Concerta · All guides
Where this information comes from
We would rather you checked us than took our word for it. Every link below is the original source, not a summary of one.
- Takeda Pharmaceuticals Australia. Vyvanse (lisdexamfetamine dimesilate) Australian Product Information (revised April 2026).The TGA-approved product information: indications, contraindications, abuse warning, pharmacokinetics, clinical trial results and side-effect frequencies.
- Takeda Pharmaceuticals Australia. Vyvanse Consumer Medicine Information (April 2026).Plain-language leaflet covering uses, who shouldn't take it, serious side effects and the rule against giving it to others.
- Healthdirect. Vyvanse.Government-funded medicine page confirming indications, specialist initiation, Schedule 8 status and the link to the TGA consumer medicine information.
- Wigal et al. (2009). A 13-hour laboratory school study of lisdexamfetamine dimesylate in school-aged children with attention-deficit/hyperactivity disorder. Child and Adolescent Psychiatry and Mental Health.Crossover trial in 129 children aged 6 to 12 measuring effects from 1.5 to 13 hours after a morning dose, with side-effect rates.
- Coghill et al. (2013). European, randomized, phase 3 study of lisdexamfetamine dimesylate in children and adolescents with attention-deficit/hyperactivity disorder. European Neuropsychopharmacology.Seven-week placebo-controlled trial in 336 children and teenagers aged 6 to 17, with a long-acting methylphenidate arm.
- Cortese et al. (2018). Comparative efficacy and tolerability of medications for attention-deficit hyperactivity disorder in children, adolescents, and adults: a systematic review and network meta-analysis. The Lancet Psychiatry.Network meta-analysis of 133 trials in which lisdexamfetamine was grouped with amphetamines, comparing short-term efficacy and tolerability.
- Farhat et al. (2025). Comparative cardiovascular safety of medications for attention-deficit hyperactivity disorder in children, adolescents, and adults: a systematic review and network meta-analysis. The Lancet Psychiatry.Analysis of 102 short trials finding small average rises in blood pressure and heart rate with stimulants, and recommending monitoring for all ADHD medicines.
- Roberts et al. (2020). How effective are pharmaceuticals for cognitive enhancement in healthy adults? A series of meta-analyses of cognitive performance during acute administration of modafinil, methylphenidate and D-amphetamine. European Neuropsychopharmacology.Meta-analyses of 47 studies in healthy adults finding no significant cognitive effect for dexamfetamine and small effects for methylphenidate.
- Ilieva et al. (2013). Objective and subjective cognitive enhancing effects of mixed amphetamine salts in healthy people. Neuropharmacology.Placebo-controlled trial in 46 healthy young adults finding no overall cognitive enhancement, although participants believed their performance had improved.
- Australasian ADHD Professionals Association (2022). Australian Evidence-Based Clinical Practice Guideline for ADHD: Summary of Recommendations.Recommends methylphenidate, dexamfetamine or lisdexamfetamine as first-line medicines without ranking them.
- Efron & Coscini (2025). Pharmacological management of attention deficit hyperactivity disorder in children and adolescents. Australian Prescriber.Australian prescribing review giving typical durations for lisdexamfetamine (6 to 12 hours) and dexamfetamine (4 to 6 hours).
- Suetani, Hull & Scott (2026). Pharmacological management of attention deficit hyperactivity disorder in adults. Australian Prescriber.Lists each medicine's TGA-registered indication and dosing frequency, and notes that misuse and diversion of stimulants are common.
- Healthdirect. Dexamfetamine (Aspen).Confirms dexamfetamine's registered indications (narcolepsy and ADHD in children) and Schedule 8 status.
- SA Health. Schedule 8 medicine treatment.States it is illegal to supply your prescription drug to another person, and explains why that is unsafe.
- Healthdirect. Stimulant drugs (last reviewed May 2025).Describes the risks of misusing stimulants, including high body temperature, seizures, coma and death at higher doses.
- Healthdirect. ADHD medicines (last reviewed December 2025).Notes that stimulants work differently in different people and that a doctor may try another if one doesn't help.
Links to external sites are provided for reference. We do not control them and they may change. Last checked 25 September 2026.