Centanafadine (Simtriyo) for ADHD: What the Label Actually Says

Why I Am Writing This Now

I published a review of the modern ADHD pharmacopeia on this site in May 2026, and in it I wrote that centanafadine, if approved, "would be the first non-stimulant ADHD medication with direct dopaminergic activity." That was the consensus reading at the time. It was also wrong, and I want to correct it directly, because the correction is more clinically useful than the original claim.

My research program at Columbia is concerned with ADHD pharmacology and the real-world consequences of treatment and non-treatment — including a 2025 JAMA Psychiatry analysis of stimulant treatment and functional outcomes in a cohort of 247,420 individuals, and a 2019 JAMA Network Open study of antipsychotic-before-stimulant prescribing in youth. That work makes me unusually interested in the gap between how a drug is described in the trade press and what its label actually commits to. With centanafadine, that gap is wide.

What follows is a read of the approved prescribing information, not of the press release. Every number below comes from the label.

The Central Surprise: This Is a Stimulant

Section 1 of the prescribing information opens with this: "SIMTRIYO is a norepinephrine-dopamine-serotonin reuptake inhibitor and central nervous system stimulant indicated for the treatment of ADHD."

The phrase "central nervous system stimulant" is not incidental language. It carries specific consequences that run through the entire label:

• The controlled substance schedule is listed as pending DEA review. The label's "Initial U.S. Approval" field is literally blank — annotated as pending scheduling.
• There is a boxed warning for abuse, misuse, and addiction, phrased in the same terms used for methylphenidate and amphetamine products: "Abuse of central nervous system (CNS) stimulants, including SIMTRIYO, can lead to the development of a substance use disorder, including addiction."
• Prescribers are instructed to assess abuse risk before initiating, to counsel families on locked storage and proper disposal, and to reassess risk and monitor for signs of misuse throughout treatment.

For years, the appeal of centanafadine in clinical conversation was precisely that it might sidestep all of this. A dopaminergic agent without Schedule II handcuffs would have been a genuinely significant addition — especially for patients with substance use histories, for families anxious about diversion, and in the context of the recurring stimulant supply shortages that have made Schedule II prescribing operationally miserable. That drug did not arrive.

The Human Abuse-Liability Data

The reason for the classification is in Section 9.2, and it is the most striking part of the label. Two human abuse-potential studies were conducted in people with a history of recreational stimulant use.

In the first study, single doses of immediate-release centanafadine 400 mg and 800 mg (roughly 2 and 4 times the adult starting dose) produced Drug Liking scores on a visual analog scale that were greater than placebo and not statistically significantly less than the scores produced by amphetamine 40 mg. The 800 mg dose likewise produced Drug Liking not statistically significantly less than lisdexamfetamine 150 mg. Centanafadine produced elevated mood in 9 to 12% of subjects, compared with 7% for amphetamine and 12% for lisdexamfetamine.

In the second study, centanafadine 200 mg, 400 mg, and 800 mg produced Drug Liking greater than placebo but less than amphetamine 15 mg and 30 mg. Euphoric mood occurred in 17 to 30% of centanafadine subjects, comparable to 19 to 35% with amphetamine.

The label's conclusion is unhedged: "These human data demonstrate that centanafadine has abuse potential."

Two observations for clinicians. First, the doses tested were supratherapeutic and used an immediate-release formulation, which is the standard design for abuse-liability work and is deliberately unfavorable to the drug — the marketed product is an extended-release capsule, and slower absorption meaningfully blunts liking. Second, and notwithstanding that, a signal statistically indistinguishable from amphetamine at any dose is not a subtle finding, and it is not the profile of atomoxetine or viloxazine, neither of which carries an abuse warning at all.

The One Real Consolation: No Physical Dependence

Section 9.3 contains the label's most genuinely favorable finding, and it deserves more attention than it will get. In the two adult phase 3 studies, abrupt discontinuation after chronic administration "produced a very low degree of withdrawal symptoms that were indistinguishable from those produced by placebo." The label draws the conclusion explicitly: "This suggests that even though SIMTRIYO is a CNS stimulant, it does not produce physical dependence."

The label also notes that centanafadine may produce tolerance, in the standard boilerplate sense, without presenting data quantifying it.

Clinically this matters. A stimulant that can be stopped without a withdrawal syndrome is easier to discontinue, easier to interrupt for drug holidays, and safer in patients whose adherence is erratic. It is a real differentiator from amphetamine-class agents. It is just not the differentiator anyone was expecting.

Dual Boxed Warnings: A First in ADHD

Simtriyo carries two boxed warnings, and the combination is unprecedented among ADHD medications.

The suicidality warning derives from a specific finding: in the 6-week pediatric study, higher rates of suicidal ideation and behavior were reported in centanafadine-treated children aged 6 to 12 than in placebo-treated children. The label requires close monitoring of all pediatric patients 6 and older, especially during the initial months, and instructs prescribers to consider stopping the drug if suicidal ideation emerges.

From a child psychiatry standpoint, this is the label's most consequential feature for the youngest patients. The population in which the suicidality signal appeared — ages 6 to 12 — is the same population in which the rash signal appeared, and it is the population with the largest measured benefit. That is an uncomfortable set of facts to hold together in a single prescribing decision, and it means the informed-consent conversation for a 7-year-old starting Simtriyo is materially longer than the one for starting methylphenidate.

The Efficacy Data, With the Numbers

Approval rested on four 6-week randomized, double-blind, placebo-controlled trials: two pediatric (Studies 1 and 2) and two adult (Studies 3 and 4).

Children 6 to 12 Years (Study 1, NCT05428033)

480 patients aged 6 to 12 randomized 1:1:1 to weight-based equivalent of 280 mg, weight-based equivalent of 140 mg, or placebo. Mean age 9 years; 58% male; 27% Black or African American, 65% White, 31% Hispanic or Latino. Primary endpoint: change from baseline at Week 6 in ADHD-RS-5 total raw score.

Note the placebo response: 10.8 points of the 16.3-point improvement occurred in the placebo arm. The drug-attributable increment is 5.6 points on a scale with a baseline of 43.

Adolescents 13 to 17 Years (Study 2, NCT05257265)

459 patients randomized 1:1:1 to 140 mg, 280 mg, or placebo. Mean age 15; 59% male.

The adolescent placebo response was larger still: 14.2 of 18.5 points.

Adults (Studies 3 and 4, NCT03605680 and NCT03605836)

906 adults aged 18 to 55 randomized across two studies. Primary endpoint: change from baseline at Day 42 on the ADHD Investigator Symptom Rating Scale (AISRS).

Three features of the adult data deserve comment.

First, there is no dose-response relationship. In Study 3 the low dose outperformed the high dose (-3.2 versus -2.7); in Study 4 the high dose was marginally better (-4.4 versus -4.0). Averaged across both studies, dose does not predict benefit. That is a meaningful finding for titration: pushing an adult from 210 mg to 280 mg has no trial-based expectation of greater efficacy, only of greater adverse effects, since nausea, dry mouth, and decreased appetite all rose with dose.

Second, the confidence interval for the Study 3 high dose extends to -0.14. That is statistical significance achieved by a margin that would not survive much perturbation.

Third, and easy to miss: the adult studies used a different formulation of centanafadine, not the marketed Simtriyo capsule. The label states that low and high doses of that other formulation are expected to be equivalent to Simtriyo 210 mg and 280 mg respectively, but the adult indication rests on a pharmacokinetic bridge rather than on trials of the actual product being sold.

Putting the Effect Sizes in Context

Converting these to approximate standardized effect sizes puts centanafadine in roughly the 0.3 to 0.4 range. For reference, in comparable short-term trials methylphenidate and amphetamine-class stimulants generally produce standardized effect sizes near 0.8 to 1.0, while atomoxetine and viloxazine sit near 0.3 to 0.5.

Centanafadine, in other words, performs like a non-stimulant. It is scheduled like a stimulant. This is the crux of the drug's positioning problem, and no amount of first-in-class mechanism language dissolves it.

The caveat matters and I will state it plainly: these are cross-trial comparisons, not head-to-head data. No trial has compared centanafadine with methylphenidate, amphetamine, atomoxetine, or viloxazine. Trial populations, placebo responses, and rating instruments differ. But the gap between 0.35 and 0.9 is large enough that methodological noise is an insufficient explanation.

Dosing: Rigid by Design

Simtriyo is supplied as 140 mg, 210 mg, and 280 mg extended-release capsules, taken once daily in the morning, with or without food, at approximately the same time each day.

Capsules must not be cut, crushed, or chewed. They may be swallowed whole, or opened and the entire contents sprinkled over one tablespoon (15 mL) of applesauce or yogurt, or into one tablespoon of orange juice, consumed immediately and followed by water. The granules must not be chewed and the mixture must not be saved for later. The sprinkle option is a real practical advantage for younger children and for patients with pill-swallowing difficulty — a constraint I discuss at length in the review of newer ADHD formulations.

The Missing Lower Rung

Here is the dosing fact with the largest practical consequence, and it is buried in Section 2.2.

In both pediatric trials, the 140 mg dose and its weight-based equivalent failed to separate from placebo. The label states it directly for each study and then draws the conclusion: "The effectiveness of SIMTRIYO 140 mg once daily in patients aged 13 to 17 years and the weight-based equivalent dosage in patients aged 6 to 12 years was not established." It goes further — 210 mg once daily and its weight-based equivalents were never studied in patients aged 6 to 17 and are "not recommended."

For pediatric prescribing this removes the maneuver clinicians rely on most. Ordinarily, when a child develops tolerable-but-annoying side effects, you reduce the dose and often keep most of the benefit. With Simtriyo in a child, the weight band determines the dose, the dose below it has no demonstrated efficacy, and the intermediate dose is explicitly not recommended. There is no titration ladder — only an on-off switch. A child either tolerates the target dose or comes off the drug.

This is a genuine and underappreciated disadvantage relative to every stimulant on the market, all of which offer fine-grained dose adjustment, and relative to atomoxetine and viloxazine, both of which have multiple efficacious dose levels.

Adverse Reactions

The safety database comprises 608 pediatric patients aged 6 and older exposed in Studies 1 and 2 (394 for at least 6 months, 286 for 12 months or longer), and 586 adults exposed to the other centanafadine formulation in Studies 3 and 4 (422 for at least 6 months, 221 for 12 months or longer). That is a reasonable long-term exposure base for a new molecular entity.

Children 6 to 12 Years (adverse reactions in at least 2%, greater than placebo)

Adolescents 13 to 17 Years

Adults (pooled Studies 3 and 4)

The Rash Signal

Rash is the adverse reaction I would counsel on most explicitly, and it is the one least likely to appear in marketing materials. In children 6 to 12 it occurred in 9% on drug versus 0% on placebo — a clean signal with no background noise. The label's definition is broad, encompassing drug eruption and macular, maculopapular, morbilliform, and papular rash. Rash also appears in the label's list of the most common adverse reactions leading to discontinuation, alongside decreased appetite, nausea, and somnolence.

Separately, Warning 5.11 addresses allergic reactions due to the inactive ingredient FD&C Yellow No. 5 (tartrazine). Whether the tartrazine content contributes to the rash incidence is not addressed in the label, but the juxtaposition is notable.

For adolescents, the standout is decreased appetite at 15% versus 2% — comparable to what one sees with stimulants, and another reminder that the "non-stimulant tolerability profile" framing does not hold up.

Warnings, Contraindications, and Interactions

The warnings section reads like a stimulant label with serotonergic additions.

Contraindications: known hypersensitivity to centanafadine or excipients; current use or use within 14 days of an MAOI; pheochromocytoma or history of pheochromocytoma.

Assessment required before initiating: abuse and addiction risk; presence of cardiac disease; heart rate and blood pressure; risk of developing a manic episode; family history of tics or Tourette's syndrome, with clinical evaluation for motor or verbal tics.

Warnings and precautions:

• Serious cardiac disease — avoid in structural cardiac abnormalities, cardiomyopathy, serious arrhythmia, coronary artery disease.
• Increased blood pressure and heart rate — assess after dose increases and periodically. Tachycardia occurred in 2% of adults at the high dose. At twice the maximum recommended dose, clinically significant QTc prolongation was not observed.
• Psychiatric adverse reactions — consider discontinuation if new psychotic or manic symptoms occur.
• Hypersensitivity reactions — anaphylaxis and angioedema have been reported.
• Long-term growth suppression in children — monitor height, weight, BMI, and linear growth; consider treatment interruption if growth falters. The label notes that children under 6 had a higher incidence of weight loss, which is the stated reason for the age and 20 kg weight floors.
• Peripheral vasculopathy including Raynaud's phenomenon — assess digital changes; consider rheumatology referral.
• Serotonin syndrome — a risk unique among ADHD agents, given the serotonergic reuptake inhibition.
• Motor and verbal tics, worsening of Tourette's syndrome — monitor regularly.

Drug interactions worth committing to memory:

• Alcohol — avoid at the same time as, and for at least two hours after, dosing. This is an unusual and specific instruction, and it will matter for adolescents and young adults.
• CYP1A2 substrates — monitor for adverse reactions; consider reducing the substrate dose.
• Other CNS stimulants — monitor for cardiovascular adverse reactions. The implication is that Simtriyo may be co-prescribed with a stimulant, but the label offers no efficacy data for that combination.
• Serotonergic drugs — serotonin syndrome risk. Relevant given how many ADHD patients carry comorbid depression or anxiety and take an SSRI or SNRI.

Simtriyo is not recommended in severe hepatic impairment.

Where Centanafadine Actually Fits

Reading the label rather than the launch narrative, my assessment is that centanafadine occupies a narrower niche than either its developers or its early enthusiasts hoped.

The Case Against Early Adoption

It offers non-stimulant efficacy with stimulant-level regulatory burden. If a patient is willing to accept a scheduled controlled substance, with the abuse counseling, storage precautions, refill logistics, and shortage exposure that entails, then methylphenidate and amphetamine-class agents offer roughly twice the effect size, decades of safety data, granular dose titration, and generic pricing. If a patient wants to avoid scheduling, atomoxetine, viloxazine, guanfacine ER, and clonidine ER remain unscheduled and deliver comparable effect sizes — and the first two are generic or approaching it.

Add the dual boxed warnings, the 9% rash rate in young children, the absence of a validated lower dose in pediatrics, the flat dose-response in adults, and the fact that adult approval rests on a formulation bridge rather than trials of the marketed product, and the case for early routine adoption is weak.

The Case For Having It Available

That said, three things are genuinely new, and in the right patient they matter.

The mechanism is real and distinct. No other approved ADHD medication inhibits serotonin reuptake. For patients who have responded partially to noradrenergic and dopaminergic agents, or whose ADHD travels with prominent emotional dysregulation, irritability, or anxiety, a serotonergic contribution is a plausible mechanistic reason to expect something different. That is a hypothesis rather than a demonstrated indication — the trials did not test comorbid populations — but mechanistic novelty is the legitimate reason to keep a drug in the armamentarium.

No physical dependence. Withdrawal indistinguishable from placebo, in a stimulant, is a real property. For patients who need to interrupt treatment, or who have struggled with amphetamine discontinuation, this is a meaningful advantage.

Once-daily with a sprinkle option. One morning dose, no afternoon redosing, no school-nurse administration, and a capsule that can be opened onto applesauce. For families managing a child who cannot swallow pills, and for adolescents whose adherence collapses under a twice-daily regimen, this is not a trivial benefit.

My Practical Position

I will not be reaching for centanafadine as a first-line or second-line agent. The patient I can see it helping is the one who has had a real but incomplete response to a well-titrated stimulant, has failed or cannot tolerate atomoxetine or viloxazine and an alpha-2 agonist, and has no cardiac contraindication, no significant tic history, and no serotonergic polypharmacy complicating the picture. That patient exists, and I see them in a treatment-resistant ADHD practice. They are not the majority.

I would also want to see three things before broader use: post-marketing data on the pediatric suicidality signal in a larger sample; the DEA schedule, which determines the real-world prescribing friction; and pricing, which will determine whether any of this is academic.

What Happens Next: DEA Scheduling

Simtriyo cannot be prescribed yet. Because the label establishes abuse potential, the DEA must assign a controlled substance schedule before marketing. Otsuka has indicated availability later in 2026.

The schedule assigned will substantially shape the drug's clinical role. Schedule II would place it under the same constraints as methylphenidate and amphetamine — no refills, quantity limits, prescription-monitoring reporting — while offering half their efficacy, which would be close to fatal to its prospects. Schedule IV, the placement given to serdexmethylphenidate and to modafinil, would preserve a real advantage: refillable prescriptions, less DEA friction, easier telehealth prescribing. The abuse-liability data cut both ways, and the outcome is genuinely uncertain.

I will update this page when the schedule is announced.

What This Analysis Does Not Replace

This is an educational analysis of a newly published prescribing information document, written for clinicians and for informed patients and families. It is not medical advice and it is not a substitute for the full label or for individualized clinical judgment. Nothing here should be used to start, stop, or change a medication.

Anyone considering centanafadine should read the complete prescribing information and discuss it with their prescriber. My reading of effect sizes across drug classes relies on cross-trial comparison, which cannot substitute for head-to-head trials; where I have drawn conclusions beyond what the label states, I have tried to say so.

Frequently Asked Questions

Is Simtriyo (centanafadine) a stimulant or a non-stimulant?

A stimulant, per the label. The prescribing information describes Simtriyo as "a norepinephrine-dopamine-serotonin reuptake inhibitor and central nervous system stimulant." Its DEA schedule is pending, it carries a boxed warning for abuse, misuse, and addiction, and human abuse-liability studies found drug-liking scores not statistically significantly lower than amphetamine 40 mg at supratherapeutic doses. This contradicts years of coverage describing centanafadine as a novel non-stimulant, including my own earlier writing on this site. It is not a non-stimulant in the way atomoxetine, viloxazine, guanfacine, or clonidine are.

How effective is centanafadine compared with stimulants?

Considerably less, on the available evidence. Placebo-subtracted improvements were 5.6 points on the ADHD-RS-5 in children 6 to 12, 4.4 points in adolescents, and 2.7 to 4.4 points on the AISRS in adults — approximate standardized effect sizes of 0.3 to 0.4. Methylphenidate and amphetamine-class stimulants typically achieve 0.8 to 1.0 in comparable trials; atomoxetine and viloxazine sit near 0.3 to 0.5. No head-to-head trials exist, so this is cross-trial comparison, but the magnitude of the gap is hard to attribute to methodology alone.

What is the dosing for Simtriyo?

140 mg, 210 mg, and 280 mg extended-release capsules, once daily in the morning, with or without food. Children 6 to 12 weighing at least 20 kg are dosed by weight: 140 mg for 20 to under 35 kg, 210 mg for 35 to 50 kg, 280 mg above 50 kg. Adolescents 13 to 17 receive 280 mg. Adults start at 210 mg and may go to a 280 mg maximum. Capsules may be opened and sprinkled on a tablespoon of applesauce, yogurt, or orange juice, consumed immediately; they must not be cut, crushed, or chewed. Note that 140 mg failed in both pediatric trials, so there is no validated lower dose for children and adolescents.

What are the boxed warnings?

Two. First, suicidal ideation and behaviors in pediatric patients 6 and older — higher rates occurred in centanafadine-treated children aged 6 to 12 than in those on placebo in a 6-week study. Second, abuse, misuse, and addiction, reflecting the CNS stimulant classification. Simtriyo is the first ADHD medication to carry both; stimulants carry the abuse warning without the suicidality warning, and atomoxetine and viloxazine carry the suicidality warning without the abuse warning.

What are the most common side effects?

Children 6 to 12: rash (9% versus 0% placebo) and decreased appetite (8% versus 3%). Adolescents: decreased appetite (15% versus 2%), nausea (10% versus 3%), rash (8% versus 1%), headache, abdominal pain. Adults at the high dose: headache (8%), decreased appetite (7%), insomnia (7%), nausea (7%), dry mouth (6%), diarrhea (5%). The rash signal in young children is the most distinctive finding — clean separation from placebo, and among the leading causes of discontinuation. The label also warns about allergic reactions to the inactive ingredient FD&C Yellow No. 5.

When will Simtriyo be available?

Later in 2026, after the DEA assigns a controlled substance schedule. The label lists both the schedule and the initial U.S. approval date as pending scheduling. Until that process completes, the drug cannot be marketed or prescribed.

Does centanafadine cause withdrawal?

Apparently not. In the two adult phase 3 studies, abrupt discontinuation after chronic dosing produced withdrawal symptoms indistinguishable from placebo. The label concludes that despite being a CNS stimulant, Simtriyo "does not produce physical dependence." The label separately notes that tolerance may develop, without quantifying it. This is the drug's clearest advantage over amphetamine-class agents.

Can centanafadine be combined with a stimulant?

The label contemplates it without endorsing it. The drug interactions section instructs prescribers to monitor for cardiovascular adverse reactions with concomitant CNS stimulants, and to consider reducing the stimulant dose or discontinuing one agent if such reactions occur. No efficacy data for the combination are presented. Given that both agents raise heart rate and blood pressure, and that neither combination efficacy nor combination safety has been formally studied, I would regard this as a specialist decision requiring cardiovascular monitoring.

Who should not take Simtriyo?

It is contraindicated with hypersensitivity to centanafadine or its excipients, with MAOI use or within 14 days of stopping an MAOI, and in pheochromocytoma or a history of it. It should be avoided in serious cardiac disease. It is not recommended in severe hepatic impairment, in children under 6, or in patients weighing under 20 kg. Caution is warranted with a personal or family history of tics or Tourette's syndrome, with bipolar disorder or mania risk, with serotonergic co-medication, and where growth suppression is already a concern.

Primary References

Further Reading

• The New ADHD Medications of 2024-2026 — the broader review this analysis updates, covering Qelbree, Azstarys, Onyda XR, and the reformulation landscape
• ADHD Pharmacology and the Natural Course of Illness — companion review of the underlying drug classes and how treatment intersects with the course of ADHD across the lifespan
• Untreated ADHD: Adverse Outcomes — the population-level evidence for why effective pharmacological treatment matters
• Choosing Between Stimulants and Non-Stimulants — the decision framework centanafadine complicates
• Stimulants vs. Non-Stimulants — the foundational class-comparison framework
• ADHD Medication Side Effects — what to expect and how to manage common adverse effects
• ADHD Medication Titration — why the absence of a validated lower dose matters so much in pediatric prescribing
• ADHD Medications and Cardiovascular Safety — relevant to the blood pressure and heart rate monitoring Simtriyo requires
• ADHD, Tics, and Tourette's Syndrome — context for the label's tic screening requirement
• Medication Titration and Dosing in Children — the pediatric dose-adjustment practices Simtriyo does not accommodate
• ADHD Drug Holidays — where the absence of a withdrawal syndrome could be an advantage
• Stimulant Shortages, Insurance, and Prior Authorization — the access problems a truly unscheduled agent would have solved
• ADHD, Substance Use, and Protective Effects of Treatment — why abuse liability in an ADHD drug matters clinically
• ADHD Medication Tolerance — when medications appear to stop working
• ADHD Medication Guide — comprehensive reference on all currently used ADHD medications
• ADHD Psychiatrist NYC — evaluation and medication management for adults and adolescents with ADHD