Centanafadine (Simtriyo) vs. Vyvanse vs. Adderall: What the Trial Numbers Show

Three medications, one indication, zero head-to-head trials

In July 2026 the FDA approved centanafadine, sold as Simtriyo, for ADHD in patients six and older. Within weeks, the question I hear most in clinic became some version of "is it better than what I'm taking?" The people asking are mostly taking one of two drugs: lisdexamfetamine (Vyvanse and its generics) or mixed amphetamine salts (Adderall and its generics). Those two agents and their methylphenidate cousins have anchored ADHD prescribing for decades.

The direct answer is that nobody has run the trial. The FDA requires a new drug to beat placebo; it does not require the comparison patients actually care about. So this post assembles the comparison from what exists: the placebo-controlled effect sizes, the indirect statistical comparisons, the tolerability data, and the practical facts of scheduling, supply, and price. I've published a full analysis of all seven centanafadine trial publications and a close reading of the Simtriyo label; this piece is the distillation for a reader choosing among three specific drugs.

The comparison at a glance

Effect size is where the three separate

Effect size is the standard yardstick for comparing medications tested only against placebo, and it's the fairest one available here. Across the four positive dose arms of the centanafadine program, spanning adults, adolescents, and children, the effect size landed between 0.24 and 0.40 (Adler et al., 2022, J Clin Psychopharmacol, 42:429-439; Ward et al., 2025, JAACAP; Ward et al., 2025, Pediatrics Open Science).

The benchmark comes from the largest network meta-analysis of adult ADHD medications: amphetamines 0.79, methylphenidate 0.49, atomoxetine 0.45 (Cortese et al., 2018, Lancet Psychiatry, 5:727-738). Centanafadine sits at the bottom of the non-stimulant range, at roughly half of amphetamine. In other words, a patient switching from a well-tolerated amphetamine to centanafadine should expect a smaller treatment effect, and the size of that step down is on the order of the difference between a stimulant and atomoxetine.

Cross-study comparisons carry real limitations: the trials differ in populations, rating scales, and placebo response. Nevertheless, the pattern is consistent across every age group tested, and it matches the pharmacology. A norepinephrine-dominant drug performing like the other norepinephrine-dominant drugs is the expected result, and the expected result is what the trials produced.

The one significant indirect comparison favored Vyvanse

Because no head-to-head trial exists, the manufacturer funded matching-adjusted indirect comparisons against four existing medications. One reached statistical significance: centanafadine performed 6.58 AISRS points worse than lisdexamfetamine (95% CI 2.72-10.43; Schein et al., 2024, J Manag Care Spec Pharm, 30:528-540).

The comparisons against methylphenidate, atomoxetine, and viloxazine found no significant difference, and these are widely quoted as showing "comparable efficacy." The confidence intervals tell a different story: each is wide enough to contain a deficit of the same 6.58 points that reached significance against lisdexamfetamine. Failing to detect a difference is different from demonstrating similarity. Those three results are underpowered nulls, and they're being reported backwards in most coverage.

Against Adderall specifically, no indirect comparison was published at all. Given that mixed amphetamine salts and lisdexamfetamine deliver the same active molecule to the brain, the lisdexamfetamine result is the closest available proxy, with the additional uncertainty that proxy status implies.

Tolerability is centanafadine's real case

The efficacy gap has a flip side, and it's genuine. In the indirect comparisons, centanafadine produced 23.42 percentage points less appetite loss, 19.27 points less dry mouth, and 15.35 points less insomnia than lisdexamfetamine. Against long-acting methylphenidate, the insomnia advantage was 9.46 fewer events per 100 patients (p=0.003; Schein et al., 2025, Can J Psychiatry, 70:629-638).

Two cautions apply. These comparisons are indirect and sponsor-funded, and across all 28 published adverse-event comparisons every single one favored centanafadine, a directional sweep that likely reflects some differential ascertainment across trials rather than pharmacology alone. Still, the core claim is biologically plausible: benefit and side effects run through the same mechanisms, so a drug that's less potent at those targets should generate proportionally less of both. Half the effect, half the side-effect burden is a coherent package. It's marketed as a free lunch; it's actually a trade.

Think of it the way you'd think about coffee. A half-caff pour disturbs your sleep less than a double espresso, and it wakes you up less. Both facts are true, both come from the same molecule, and which cup you want depends on what you need from the morning.

Scheduling, supply, and price

Vyvanse and Adderall are Schedule II controlled substances subject to DEA Aggregate Production Quotas, which is why both have spent years on the FDA shortage list: mixed amphetamine salts since October 2022, lisdexamfetamine in spot shortages since the August 2023 generic launch. I've written a full analysis of the shortage's structural causes; the short version is that supply failure is now a routine clinical problem for amphetamine patients.

Centanafadine's status is different in both directions. As of August 2026 the DEA has not yet issued its scheduling decision, and Simtriyo is not yet available in pharmacies; availability is expected later in 2026. The label carries a boxed warning for abuse and misuse, and in human abuse-liability studies, drug liking at high doses was not statistically lower than amphetamine's, so some scheduling restriction appears likely. My read of the data is that it lands below Schedule II, which would exempt it from the quota system that drives stimulant shortages. If that holds, reliable supply becomes one of its legitimate selling points.

Price runs the other way. Generic lisdexamfetamine and generic mixed amphetamine salts cost a few dollars a month on many plans. Simtriyo launches brand-only, and insurers will likely require prior authorization with documented failure of cheaper agents first. For a patient whose current medication works and stays in stock, the economics alone argue for staying put.

Who each drug actually fits

Based on the trial data and the label, centanafadine's plausible place involves four groups: patients with moderate rather than severe symptoms, particularly predominantly inattentive presentations, where the week-1 data showed its earliest effect; patients for whom insomnia or appetite suppression has blocked stimulant treatment; patients with a history of stimulant misuse; and patients whose amphetamine supply keeps failing. Those are real populations, and I see all four in practice.

The amphetamines keep their place for the majority: patients with moderate-to-severe symptoms who need the full treatment effect, established responders, and anyone for whom cost matters. The within-individual registry evidence on what consistent stimulant treatment protects against, from motor-vehicle crashes to substance-use events, was built on the existing agents, and a smaller treatment effect plausibly buys less of that protection, although no trial has tested the question directly.

One more caveat belongs in every conversation about this drug: the pediatric boxed warning for suicidal ideation and behavior in children ages 6-12 is a first among ADHD medications, and any parent weighing Simtriyo for a child should discuss it explicitly with the prescriber.

New medications deserve neither hype nor cynicism. They deserve arithmetic. On the arithmetic available in August 2026, Simtriyo is a smaller drug with a gentler ride and an unresolved price and scheduling picture, and the sensible clinical posture is to match it to the patients whose problem it actually solves while staying vigilant for the head-to-head data that would settle the rest.

Frequently Asked Questions

Is Simtriyo better than Vyvanse?

No trial has compared them directly. The only statistically significant indirect comparison found centanafadine 6.58 AISRS points worse than lisdexamfetamine (95% CI 2.72-10.43; Schein 2024). On placebo-controlled effect sizes, centanafadine clusters at 0.24-0.40 while amphetamines benchmark at 0.79 in the Cortese 2018 network meta-analysis. Simtriyo's advantage is tolerability, particularly insomnia and appetite, and that advantage is real in the published data. For symptom reduction, the numbers favor Vyvanse.

Is Simtriyo a stimulant or a non-stimulant?

Both labels are in circulation, and the FDA prescribing information settles it: Simtriyo is classified as a central nervous system stimulant, while most media coverage calls it a non-stimulant. Pharmacologically it is norepinephrine-dominant (6-fold less potent at the dopamine transporter and 14-fold less potent at the serotonin transporter than at the norepinephrine transporter), which places its clinical behavior closer to atomoxetine than to Adderall. Its trial effect sizes match the non-stimulant class.

Can I switch from Adderall to Simtriyo?

The switch is a clinical decision to make with a prescriber, and two facts should inform it. First, no conversion ratio exists because the drugs act through different transporter profiles; Simtriyo starts at 210 mg once daily in adults with a maximum of 280 mg. Second, a patient who has responded well to an amphetamine should expect less symptom reduction on centanafadine, since its effect sizes run at roughly half of amphetamine's. The switch makes most sense when side effects, misuse history, or supply failure limit the current stimulant.

Does Simtriyo cause less insomnia than stimulants?

Insomnia is Simtriyo's best-documented advantage. In indirect comparison it produced 9.46 fewer insomnia events per 100 patients than long-acting methylphenidate (p=0.003; Schein 2025) and 15.35 percentage points fewer than lisdexamfetamine. Appetite loss ran 23.42 percentage points lower than lisdexamfetamine. These comparisons are sponsor-funded and indirect, but the direction is consistent with the pharmacology: a less potent drug at the relevant transporters should produce proportionally less of both benefit and side effect.

When will Simtriyo be available and will insurance cover it?

As of August 2026, Simtriyo is FDA-approved but not yet in pharmacies; availability awaits the DEA scheduling decision, expected later in 2026. It launches as a brand-only product with no generic, so prior authorization requirements are likely, and insurers will typically require documented trials of generic stimulants or non-stimulants first. Generic lisdexamfetamine and generic mixed amphetamine salts remain the low-cost options when supply allows.

Was Simtriyo ever tested head-to-head against another ADHD medication?

No. The FDA requires superiority to placebo, and every centanafadine registration trial used placebo as the comparator. The comparative claims in circulation come from matching-adjusted indirect comparisons funded by the manufacturer. One reached statistical significance, favoring lisdexamfetamine by 6.58 points. The comparisons against methylphenidate, atomoxetine, and viloxazine found no significant difference, and their confidence intervals are wide enough to contain a deficit of the same size, so they are underpowered nulls rather than evidence of equivalence.

Primary References

Further Reading

• Centanafadine (Simtriyo): What the Label Actually Says — Close reading of the FDA prescribing information, including both boxed warnings and the dosing bridge.
• Centanafadine: A Deep Analysis of the Primary Literature — All seven trial publications, with computed effect sizes and figures.
• New ADHD Medications 2024-2026 — The full pipeline: Qelbree, Azstarys, Onyda XR, Vyvanse generics.
• The 2025-2026 ADHD Stimulant Shortage — Why amphetamine supply keeps failing and how to keep a fill going.
• Non-Stimulant ADHD Medications — Atomoxetine, viloxazine, guanfacine, and clonidine compared.
• ADHD Pharmacology & Natural Course — Mechanism of stimulant action and the trajectory of untreated ADHD.
• Stimulant Medications & Protective Effects — The within-individual evidence on crashes, substance use, and criminal-justice contact.
• ADHD Medication Side Effects — Common and serious adverse effects across stimulant and non-stimulant agents.
• ADHD Psychiatrist NYC — Dr. Sultan's clinical practice for evaluation and medication management.

This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Medication decisions belong in a conversation with a qualified prescriber who knows your history.