Lisdexamfetamine

Is lisdexamfetamine safe?

For people with ADHD who are screened and followed by a prescriber, it is an effective and generally well tolerated medicine. Lisdexamfetamine is sold as Vyvanse in the US and Elvanse in the UK, and has been generic in the US since 2023. It is approved for ADHD from age 6 and for moderate to severe binge eating disorder in adults.

The catch is that it is still amphetamine once it reaches the blood. It is a Schedule IIControlled substanceA medicine or drug that the law restricts because it can be misused or cause dependence. Countries group them into schedules or classes.More in the glossary controlled substance with the same boxed warningBoxed warningThe strongest safety warning the US FDA puts on a medicine's label, printed inside a black border at the top.More in the glossary on abuse, misuse and addiction as Adderall, and it raises pulse and blood pressure. We score it 55, two points above amphetamine salts (53) and three below methylphenidate (58).

How the prodrug design works

Lisdexamfetamine is dexamfetamine with an amino acid (lysine) attached. In that form it does nothing. After it is swallowed, red blood cells slowly cut the lysine off, releasing dexamfetamine over several hours. The label gives lisdexamfetamine itself a half-life under an hour, while the dexamfetamine it produces lasts about 9 hours.

This has two practical effects. One morning dose covers the school or working day without the peaks and drops of short-acting tablets. And because the conversion cannot be sped up by crushing, the "rush" that drives misuse is blunted. In the label's study of 38 people with a history of drug use, 100 mg produced less "drug liking" than 40 mg of immediate-release dexamfetamine. But 150 mg produced as much, and injected lisdexamfetamine still produced euphoria, if less than injected dexamfetamine. The design lowers misuse risk; it does not remove it.

Side effects at prescribed doses

The label's 4-week adult ADHD trial gives the clearest picture:

Side effect	Lisdexamfetamine	Placebo
Decreased appetite	27%	2%
Insomnia	27%	8%
Dry mouth	26%	3%
Diarrhoea	7%	0%
Nausea	7%	0%
Anxiety	6%	0%

Six per cent stopped because of side effects, against 2% on placebo. In children aged 6 to 12, 39% had a lower appetite and 9% lost weight in 4 weeks, so the label asks for growth checks. Since September 2025 it also says the drug is not recommended for children under 6, who had higher blood levels and more weight loss.

The serious risks are those of every stimulant. Blood pressure rises by 2 to 4 mm Hg and heart rate by 3 to 6 beats a minute on average, more in some people. Sudden death has occurred in people with structural heart problems, which is why the label asks for a heart history, including family sudden deaths, before starting. Psychosis or mania can appear, and fingers and toes can turn pale or painful (Raynaud's).

Misuse, dependence and the 2023 warning

On 11 May 2023 the FDA required a uniform boxed warningBoxed warningThe strongest safety warning the US FDA puts on a medicine's label, printed inside a black border at the top.More in the glossary across prescription stimulants. It came after concern about misuse, addiction and overdose, and the finding that many people who misuse stimulants get them from family or friends. The Vyvanse label now asks prescribers to assess each patient's risk of misuse before starting and to keep checking during treatment. It also warns that snorting or injecting raises the risk of overdose and death.

In the UK, the Advisory Council on the Misuse of Drugs recommended in 2013 that lisdexamfetamine be controlled like dexamfetamine, as a Class B, Schedule 2 drug, because it converts so easily to amphetamine. Physical dependenceDrug dependenceThe body's adaptation to a drug taken regularly, so that stopping it suddenly causes withdrawal symptoms. It is not the same as addiction.More in the glossary is possible after long use; stopping suddenly can bring low mood, fatigue, vivid dreams and changes in sleep and appetite.

Store it locked away, never share it, and return unused capsules through a take-back scheme or pharmacy.

Binge eating disorder, not weight loss

The binge eating approval came on 30 January 2015, based on two 12-week trials in adults. The usual dose is 50 to 70 mg a day. In those trials, dry mouth (36% vs 7%), insomnia (20% vs 8%) and a faster heart rate (7% vs 1%) were the main effects. The label is explicit that lisdexamfetamine is not approved for weight loss or obesity, and that other stimulant-type weight-loss drugs have caused serious heart problems.

Who should be careful

Talk to your doctor or pharmacist before starting lisdexamfetamine, or before adding another medicine, if you:

• have heart disease, a heart rhythm problem, high blood pressure, or a family history of sudden death
• have had psychosis, bipolar disorder, depression or tics
• have a past or present problem with alcohol or drugs
• take an MAOI antidepressant or have taken one in the last 14 days
• take SSRIs, SNRIs, triptans, tramadol or other serotonin drugs
• have kidney disease, are pregnant or breastfeeding

In an overdose, call 911 or Poison Help on 1-800-222-1222 in the US, or 999 in the UK. A lower score is no reason to stop a medicine that is working; any change should be planned with your prescriber.

How we scored it

Track record (85) is good, though shorter than for older stimulants. Dependence (30) and regulatory warnings (25) are the weakest factors because of Schedule IIControlled substanceA medicine or drug that the law restricts because it can be misused or cause dependence. Countries group them into schedules or classes.More in the glossary status and the boxed warningBoxed warningThe strongest safety warning the US FDA puts on a medicine's label, printed inside a black border at the top.More in the glossary. Serious side effects (60) and overdose marginOverdose marginHow far a normal dose is from a harmful one. A wide margin means an accidental extra dose is unlikely to cause serious harm.More in the glossary (60) reflect the stimulant heart and psychiatric risks, with a small credit for the prodrug's smoother effect.