The U.S. Food and Drug Administration has approved Simtriyo, a new once-daily medication for attention-deficit/hyperactivity disorder, or ADHD, in adults and children aged 6 and older.
Developed by Japanese pharmaceutical company Otsuka, Simtriyo contains the active ingredient centanafadine and is administered as an extended-release capsule. It was approved for adults and for children weighing at least 20 kilograms, or about 44 pounds.
Otsuka said the drug is expected to become commercially available in the United States later this year, after the U.S. Drug Enforcement Administration completes the process of classifying it as a controlled substance. The FDA granted its approval on July 24, 2026.
Simtriyo is the first and only ADHD treatment approved as a norepinephrine, dopamine and serotonin reuptake inhibitor, or NDSRI. By inhibiting the reabsorption of all three neurotransmitters, the drug increases their availability in brain pathways involved in attention and behavioral regulation.
The company describes Simtriyo as a central nervous system stimulant. Analysts at Jefferies, cited by Fierce Pharma, said the FDA likely classified it as a stimulant because of its effects on the brain’s dopamine system.
Symptoms improved within the first week
The approval was based on four Phase 3 clinical trials involving children, adolescents and adults. The studies found statistically significant improvements in ADHD symptoms among patients receiving Simtriyo compared with those given a placebo.
Two trials involving more than 800 adults found that a greater proportion of patients treated with Simtriyo achieved an improvement of at least 18 points on an ADHD symptom-rating scale after six weeks. Signs of improvement were observed as early as the first week of treatment.
The drug was also tested in separate trials involving children aged 6 to 12 and adolescents aged 13 to 17.
Adolescents received either a high dose of 328.8 milligrams once daily, a lower dose of 164.4 milligrams or a placebo. Doses for younger children were adjusted according to their weight. Children and adolescents receiving the higher dose showed a significant reduction in symptoms, as measured by the ADHD-RS-5 rating scale, compared with the placebo groups.
Researchers said the drug demonstrated a generally favorable and well-characterized safety profile across the four trials, although side effects were reported.
Among children aged 6 to 12, the most common side effects were rash and reduced appetite. Adolescents most commonly experienced reduced appetite, nausea, rash, headache and abdominal pain.
In adults, the most frequently reported side effects included headache, reduced appetite, insomnia, nausea, dry mouth and diarrhea.
About a month before the FDA approval, Otsuka also reported positive preliminary findings from a Phase 3b trial involving adults with both ADHD and anxiety. The company said centanafadine was more effective than placebo in reducing ADHD symptoms among those patients.
A disorder that affects each patient differently
ADHD is a chronic neurodevelopmental disorder characterized by persistent difficulties with attention, impulse control and, in some cases, hyperactivity. Symptoms begin in childhood but may continue into adulthood and can affect education, employment, relationships and everyday functioning.
An estimated 7 million U.S. children between the ages of 3 and 17 have at some point been diagnosed with ADHD, according to the Centers for Disease Control and Prevention. Separate CDC data estimate that 15.5 million American adults, or about 6% of the adult population, currently have the disorder.
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Stimulants are the most widely used medications for ADHD, but many patients discontinue treatment or switch drugs because of inadequate effectiveness, side effects or changes in their medical needs and circumstances.
“Even with treatment, because ADHD presents differently in each person, many patients continue to experience symptoms that can impair their daily functioning,” said Dr. Lenard Adler, director of the Adult ADHD Program at NYU Langone Health and an investigator in the Simtriyo trials.
“The approval of Simtriyo introduces a new mechanism of action and expands the range of options available to health care professionals and patients,” he said in an Otsuka statement cited by Medscape.
Adler said a range of treatment options was important because ADHD affects patients differently and therapy must be tailored to each person’s symptoms, needs and response.
Current treatments and the new option
Professor Iris Manor, director of the ADHD unit at Geha Mental Health Center, part of Israel’s Clalit health care system, said the medical community has increasingly come to recognize ADHD as a complex condition that may be associated with processes elsewhere in the body.
“Today, both globally and in Israel, ADHD is increasingly regarded as a medical condition in every sense,” she said.
“Researchers are also examining whether inflammatory mechanisms are involved, alongside genetic and hereditary factors. We see associations with physical conditions that many physicians are still not sufficiently familiar with, including asthma, atopic dermatitis, obesity, diabetes and various infections. Higher levels of cytokines, proteins involved in inflammatory processes, have also been found.”
The most common pharmacological treatment remains stimulant medication, including Ritalin and Attent.
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“These drugs and their derivatives are currently considered the most effective treatments,” Manor said. “However, they have side effects, and around 15% to 20% of patients do not respond well to them. Some do not respond to the treatment itself, while others have to stop because of significant side effects.”
One of the main nonstimulant options currently available in Israel is atomoxetine, marketed under brand names including Strattera and Atomic.
“It is considered less effective than stimulant medication, but it also has a different side-effect profile,” Manor said.
Another option is guanfacine, also marketed as Intuniv. After years of efforts to obtain public funding, the drug was added to Israel’s 2026 state-subsidized health basket as a third-line treatment for children and adolescents aged 6 to 17.
It may be used alone or in combination with a stimulant.
“It works through a different mechanism that is directed more toward regulation,” Manor said.
Most side effects were mild to moderate
Centanafadine partly resembles atomoxetine in the way it works, but has a broader mechanism. While atomoxetine primarily inhibits norepinephrine reuptake, Simtriyo acts on norepinephrine, dopamine and serotonin.
“The drug was studied in both children and adults, and in my assessment it may be more effective than atomoxetine,” Manor said.
“The side effects identified in the studies were mostly mild to moderate. Unfortunately, we do not yet have experience with it because it is not available in Israel. I assume it will first be distributed in the United States, and then we will have to work to bring it to Israel as well.”
Before Simtriyo can reach U.S. pharmacies, the DEA must determine how it will be scheduled under federal controlled-substance rules. The process is standard for stimulant drugs that act on the central nervous system and may take up to three months.
That classification could affect how widely and easily the medication is prescribed. A stricter designation, similar to those applied to Vyvanse and Adderall, could limit access. A less restrictive classification could give Simtriyo an advantage over competing ADHD medications.
Analysts have said the drug could expand the broader market for alternatives to traditional ADHD stimulants, rather than merely taking patients from existing treatments such as Qelbree and Strattera.
Otsuka acquired the rights to centanafadine in 2017. The company also markets the antipsychotic medications Rexulti and Abilify Maintena for schizophrenia and other psychiatric conditions.