Lisdexamfetamine: what it treats, how to take it, side effects
Last updated September 3, 2026.
Lisdexamfetamine is a once-daily stimulant that your body converts into its active form after you swallow it. You may know it as Vyvanse. That conversion step makes its effect smoother and slower to abuse than older stimulants - but it is still a controlled substance with the full warning set. This page is information only - prescriptions for controlled substances always come from your own prescriber.
What does it treat?
ADHD in adults and children 6 and older, as part of a treatment program, and binge eating disorder in adults. One thing it must never be used for: weight loss in people who are overweight or obese.
How do you take it?
Once a day in the morning, with or without food, same time every day. The label starts at 30 mg once daily, increasing in 10 or 20 mg steps at about weekly intervals, with 70 mg a day the maximum. Never take it in the late afternoon or evening. The capsule can be swallowed whole or opened and dissolved entirely in yogurt, water, or orange juice - drink it right away, never store the mixture, never split a capsule into partial doses. Chewable tablets are chewed thoroughly. Your doctor may pause it periodically to check it is still needed. Missed dose: take it when you remember unless the next one is close; never double up.
Side effects to know
- Common: sleepiness, dizziness, headache, dry mouth, constipation, diarrhea, nausea, and weight loss. In children it can slow growth - the doctor tracks height and weight.
- Serious: MedlinePlus puts it bluntly - lisdexamfetamine may cause sudden death in children and teenagers with heart defects or serious heart problems, and sudden death, heart attack, or stroke in adults with the same. Chest pain, shortness of breath, or fainting mean calling the doctor right away. Also serious: slow or difficult speech, weakness or numbness of an arm or leg, seizures, hallucinations, paranoia, believing things that are not true, mood swings, new motor or verbal tics, circulation problems in fingers and toes (pale or blue color, pain, unexplained wounds), allergic reactions with facial swelling, and vision changes.
Who should not take it?
Anyone with a personal or family history of heavy alcohol use, street drugs, or prescription overuse - MedlinePlus says your doctor will probably not prescribe it. Flag heart defects, heart problems, high blood pressure, mental health conditions, circulation problems, and any allergy to stimulant medications. The habit-forming warning stands: exact dose, no more often, no longer, and no sudden stops after overuse - severe depression and extreme tiredness can follow. Never sell or share it: sharing a controlled substance is illegal, store it securely, and keep count of your capsules.
When is it an emergency?
Call 911 for chest pain, fainting, seizures, or stroke signs like one-sided weakness or garbled speech. Hallucinations, paranoia, and allergic swelling mean immediate care. Any thought of harming or killing yourself or others means calling your doctor immediately, or call or text 988, the Suicide and Crisis Lifeline, any time. For an overdose, call Poison Control at 1-800-222-1222. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
How is Vyvanse different from Adderall?
The prodrug design. Lisdexamfetamine is inactive until your body converts it, which gives a smoother onset and once-daily morning dosing, versus Adderall XR's bead-based release or the immediate-release tablet's 2-to-3-times-a-day schedule. Same stimulant class, same warnings - the difference is the curve, not the chemistry of the destination.
Why is there a warning about sudden death?
Because of hearts, not typical users. MedlinePlus says lisdexamfetamine may cause sudden death in children and teenagers who have heart defects or serious heart problems, and sudden death, heart attack, or stroke in adults with the same. That is why the prescriber asks about your heart history and family history before the first dose - and why chest pain, shortness of breath, or fainting on it means calling the doctor right away.
Is Vyvanse used for weight loss?
Never. MedlinePlus says lisdexamfetamine should not be used for weight loss in people who are obese or overweight. Its adult binge-eating-disorder approval is about the binge cycle, not the scale - appetite suppression is a side effect, not an indication.
Can I drink alcohol while taking Vyvanse?
There is no label-level alcohol ban, but MedlinePlus tells you to disclose any heavy drinking history before starting - and with that history, your doctor will probably not prescribe it at all. A stimulant also masks how impaired alcohol is making you. Bring it up with your prescriber honestly.
Why can't I save half a capsule for later?
Because the dose is the whole thing. MedlinePlus says if you open the capsule and dissolve the contents in yogurt, water, or orange juice, swallow it right away - do not store the mixture, and do not divide one capsule into more than one dose. If you need a lower dose, your prescriber writes a lower-strength capsule.
Is Vyvanse addictive?
It can be, despite the smoother design. MedlinePlus says lisdexamfetamine can be habit-forming, and overuse may cause behavior changes, serious heart problems, or sudden death. The safeguards: exact prescribed dose, morning only, secure storage, capsule counts, and honest disclosure of any substance-use history.