Medication approval journey
lisdexamfetamine (Vyvanse)
Approved for ADHD in children aged 6 to 12
Before changing anything
Stopping abruptly causes withdrawal effects that can be severe
Stopping a stimulant abruptly after regular use commonly causes a crash — fatigue, low mood, heavy sleep. It is not usually dangerous, but it is worth planning rather than improvising.
How long the trials actually ran
The longest trial behind the lisdexamfetamine approval ran 4 weeks.
The gap between how long the trials ran and how long people actually take these medications is the single most important thing on this page. It is not evidence that longer use is unsafe or ineffective. It is evidence that longer use was not what got tested.
The boxed warning
The strongest warning the FDA puts on a label, reproduced word for word — not our summary of it.
WARNING: ABUSE, MISUSE, AND ADDICTION Lisdexamfetamine dimesylate has a high potential for abuse and misuse, which can lead to the development of a substance use disorder, including addiction. Misuse and abuse of CNS stimulants, including lisdexamfetamine dimesylate, can result in overdose and death [see Overdosage (10) ] , and this risk is increased with higher doses or unapproved methods of administration, such as snorting or injection. Before prescribing lisdexamfetamine dimesylate, assess each patient’s risk for abuse, misuse, and addiction. Educate patients and their families about these risks, proper storage of the drug, and proper disposal of any unused drug. Throughout lisdexamfetamine dimesylate treatment, reassess each patient’s risk of abuse, misuse, and addiction and frequently monitor for signs and symptoms of abuse, misuse, and addiction [see Warnings and Precautions (5.1) , Drug Abuse and Dependence (9.2) ] . WARNING: ABUSE, MISUSE, AND ADDICTION See full prescribing information for complete boxed warning. Lisdexamfetamine dimesylate has a high potential for abuse and misuse, which can lead to the development of a substance use disorder, including addiction. Misuse and abuse of CNS stimulants, including lisdexamfetamine dimesylate, can result in overdose and death ( 5.1 , 9.2 , 10 ): Before prescribing lisdexamfetamine dimesylate , assess each patient’s risk for abuse, misuse, and addiction. Educate patients and their families about these risks, proper storage of the drug, and proper disposal of any unused drug. Throughout treatment, reassess each patient’s risk and frequently monitor for signs and symptoms of abuse, misuse, and addiction.
FDA label effective August 28, 2026 — read the full label on DailyMed
How many Americans take lisdexamfetamine
Survey-based federal estimates, published with a lag of about two years. They count prescriptions filled, not outcomes.
- 9,929,931
- prescriptions in the United States (2024)
- 1,604,929
- people filling them (2024)
Prescriptions are up 18% since 2014. Whatever you decide about lisdexamfetamine, you are deciding alongside about 1,604,929 other people this year.
Source: ClinCalc DrugStats (Medical Expenditure Panel Survey (MEPS), Agency for Healthcare Research and Quality), CC BY-SA 4.0, release 2026.08.
What people report to the FDA about lisdexamfetamine
Read this before the numbers.
Anyone can file an adverse event report — patients, doctors, manufacturers — and nobody verifies that the drug caused what was reported. There is no denominator: tens of millions of prescriptions generate reports at an unknowable rate, and reporting rises with news coverage, not necessarily with harm. Counts below are report volumes, not rates, and cannot be compared between drugs. The FDA itself says not to use this data to make medical decisions — we show it because you deserve to see what is in the public record, with its limits stated plainly.
- 34,602
- reports mentioning lisdexamfetamine, all time
- 14,462
- filed as serious (a report-level flag covering every drug and outcome in the report)
Most-reported reactions
- Drug ineffective4,950
- Fatigue2,150
- Off label use2,115
- Anxiety1,944
- Headache1,857
- Nausea1,642
- Product availability issue1,587
- Insomnia1,570
- Depression1,434
- Feeling abnormal1,401
“Drug ineffective” ranking this high is worth noticing: a report of not being helped counts as an adverse event too, and people file them in large numbers.
Source: FDA Adverse Event Reporting System (FAERS), via openFDA, data through 2026-07-30.
Known interactions, from the label
The FDA label’s interactions section, verbatim. A pharmacist checking your actual medication list beats any published list — including this one.
Read the label’s interactions section
7 DRUG INTERACTIONS Acidifying and Alkalinizing Agents: Agents that alter urinary pH can alter blood levels of amphetamine. Acidifying agents decrease amphetamine blood levels, while alkalinizing agents increase amphetamine blood levels. Adjust lisdexamfetamine dimesylate dosage accordingly. ( 2.6 , 7 .1 )
7.1 Drugs Having Clinically Important Interactions with Amphetamines Table 5: Drugs having clinically important interactions with amphetamines. MAO Inhibitors (MAOI) Clinical Impact MAOI antidepressants slow amphetamine metabolism, increasing amphetamines effect on the release of norepinephrine and other monoamines from adrenergic nerve endings causing headaches and other signs of hypertensive crisis. Toxic neurological effects and malignant hyperpyrexia can occur, sometimes with fatal results. Intervention Do not administer lisdexamfetamine dimesylate during or within 14 days following the administration of MAOI [see Contraindications (4) ] . Serotonergic Drugs Clinical Impact The concomitant use of lisdexamfetamine dimesylate and serotonergic drugs increases the risk of serotonin syndrome. Intervention Initiate with lower doses and monitor patients for signs and symptoms of serotonin syndrome, particularly during lisdexamfetamine dimesylate initiation or dosage increase. If serotonin syndrome occurs, discontinue lisdexamfetamine dimesylate and the concomitant serotonergic drug(s) [see Warnings and Precautions (5.7) ] . CYP2D6 Inhibitors Clinical Impact The concomitant use of lisdexamfetamine dimesylate and CYP2D6 inhibitors may increase the exposure of dextroamphetamine, the active metabolite of lisdexamfetamine dimesylate compared to the use of the drug alone and increase the risk of serotonin syndrome. Intervention Initiate with lower doses and monitor patients for signs and symptoms of serotonin syndrome particularly during lisdexamfetamine dimesylate initiation and after a dosage increase. If serotonin syndrome occurs, discontinue lisdexamfetamine dimesylate and the CYP2D6 inhibitor [see Warnings and Precautions (5.7) and Overdosage (10 )] . Alkalinizing Agents Clinical Impact Urinary alkalinizing agents can increase blood levels and potentiate the action of amphetamine. Intervention Co-administration of lisdexamfetamine dimesylate and urinary alkalinizing agents should be avoided. Acidifying Agents Clinical Impact Urinary acidifying agents can lower blood levels and efficacy of amphetamines. Intervention Increase dose based on clinical response. Tricyclic Antidepressants Clinical Impact May enhance the activity of tricyclic or sympathomimetic agents causing striking and sustained increases in the concentration of d-amphetamine in the brain; cardiovascular effects can be potentiated. Intervention Monitor frequently and adjust or use alternative therapy based on clinical response.
7.2 Interference with Laboratory Test Allow for an adequate washout period between administration of lisdexamfetamine dimesylate and radioactive diagnostic agents used for dopamine transporter (DAT) visualization. Lisdexamfetamine dimesylate can interfere with the test results of a radioactive diagnostic agent (ioflupane I-123) that is used for DAT visualization by binding and internalization of the DAT, which may result in lower DAT in the striatum. This may lead to false-positive diagnostic results.
FDA label for lisdexamfetamine, effective August 28, 2026 — DailyMed.
Who pays for lisdexamfetamine
Two claims datasets and one survey, covering different populations with different instruments — they cannot be reconciled by arithmetic, and where their sum crowds the all-payer estimate, that is a finding about the estimates rather than a percentage.
- Medicare Part D
- Read the under-65 group correctly before the numbers: Medicare before 65 means the disabled and dual-eligible population — among the sickest, highest-need people in the program — and reading their utilization as typical adult use would be a category error. The beneficiary total sums brand-level rows, so treat it as an upper bound on distinct people. 87,449 beneficiaries filled 409,790 claims in 2024 — 36,205 aged 65 and over, and 51,244 under 65.
- Medicaid
- At least 3,763,488 prescriptions in 2024 — a floor, because 28 of 694 national data rows are suppressed for privacy and contribute zero. Medicaid covers more children than any insurer in the country and publishes no age split — how much of this number is pediatric use is not knowable from public data.
- All payers (survey estimate)
- The MEPS-based estimate above puts the whole country at 9,929,931 prescriptions and 1,604,929 people in 2024. Subtracting the public programs from it would produce a number for everyone else — and we do not print that number, because subtracting a survey from claims counts manufactures precision that does not exist.
- The population nobody counts
- The commercially insured working-age adult — statistically, the likeliest person to be reading this page — is the one population with no public per-drug count anywhere. Private claims data exists and is sold, but nothing a patient can check is published. For children the record is thinner still: no public source counts pediatric use of lisdexamfetamine specifically; the closest the public record comes is condition-level treatment rates for children, which we have traced for one condition in how childhood ADHD got counted.
Sources: Medicare Part D Prescribers — by Geography and Drug, data.cms.gov, National rows, data year 2024 (published with ~17-month lag). Medicaid State Drug Utilization Data 2024, data.medicaid.gov, national aggregate rows. Retrieved 2026-09-01.
The approval, step by step
Step 1
What the approval was actually based on
Which studies did the FDA rely on, how long did they run, and who was in them?
A double-blind, randomized, placebo-controlled, parallel-group study (Study 1) was conducted in pediatric patients ages 6 to 12 years (N=290)... for a total of four weeks of treatment.
FDA-approved labelling, 14 CLINICAL STUDIES 14.1 Attention Deficit Hyperactivity Disorder (ADHD) — read the label on DailyMed
Our reading
The original approval was a four-week trial in 290 children aged 6 to 12. Approved in 2007, it is the newest entry here and the only one registered after ClinicalTrials.gov registration became mandatory — so its trials were preregistered, which the rubric credits.
Step 2
The approval
When was it approved, under what application, and by whose review?
- Approved
- February 23, 2007
- Application
- NDA021977
- Review
- STANDARD
- Original sponsor
- Shire (now Takeda)
- Holds it now
- Takeda Pharmaceuticals USA
- Label submissions since
- 44
Source: openFDA Drugs@FDA, original application ORIG-1
Step 3
What was added after it was on the market
Which warnings arrived only after millions of people were already taking it?
The stimulant boxed warning was rewritten in 2023
16 years after approval
In May 2023 the FDA required the boxed warning on the entire prescription stimulant class — amphetamines and methylphenidates both — to be updated. The specific gap it was closing is unusual and worth knowing: the old labels did not adequately say that most people who misuse these medications get them from a family member or a peer, and that sharing them can cause a substance use disorder in the person you share them with.
This was an update to a warning that already existed, not a new alarm about the medication working. Stimulants remain first-line treatment for ADHD.
Worth asking
How should I be storing this, how do we dispose of what I do not use, and how will we monitor whether my dose is still right over time.
Step 4
What independent research has found since
What has been learned by people who were not selling it?
Amphetamine-type ADHD medicines are reported for psychosis more often than methylphenidate
17 years after approval
Using VigiBase, the WHO's global database of adverse-drug-reaction reports, researchers compared how often psychotic symptoms were reported for amphetamine-type medications — dexamfetamine and lisdexamfetamine — against methylphenidate, in people aged 13 to 25. Across 13,863 reports there were 169 psychosis reports on amphetamines and 221 on methylphenidate, giving a reporting odds ratio of 1.61 (95% CI 1.26 to 2.06). Restricted to reports where the indication was ADHD, it was 1.94. Atomoxetine showed no association.
What this design can tell you is narrow, and pretending otherwise would be the mistake. A reporting odds ratio compares how often something is reported, not how often it happens. There is no denominator of people taking the drug, so no rate can be calculated from it. Reporting is voluntary and is influenced by publicity — a drug in the news gets reported more. And the comparison is against methylphenidate, not against nothing, so the result says amphetamines are reported more than methylphenidate, not that either one causes psychosis at any particular rate.
One more limit that matters if you take Vyvanse specifically: lisdexamfetamine was pooled with dexamfetamine in the exposure group. The study cannot separate them, so it says nothing about lisdexamfetamine on its own.
What it is good for is a question. If two medications treat the same condition and one is reported for psychosis more often, that is worth raising before you assume they are interchangeable.
Worth asking
Is there a reason we chose an amphetamine over methylphenidate for me, is there anything in my history or my family's that makes psychosis more of a concern, and what would the early signs look like.
Step 5
What still is not known
Which questions you might reasonably have has nobody answered yet?
- Four weeks in children. Adults now take this for decades — an extrapolation across both age and duration.
- The stimulant boxed warning was rewritten in 2023 to address misuse and dependence, sixteen years after approval.
- What is the evidence on cardiovascular effects and on growth over years rather than weeks?
Deciding about lisdexamfetamine?
- 12 questions to ask before starting a psychiatric medication — each with the study behind it
- Already on it? The 10-question annual review — including the honest case for staying
- How long every drug here was tested before approval — one chart, all medications
Open lisdexamfetamine (Vyvanse) in Resolv
The app has the full approval journey, the resources behind it, and people working through the same questions.
