How Simtriyo (Centanafadine) Works
Centanafadine (Simtriyo®) is a first-in-class triple monoamine reuptake inhibitor that blocks the reuptake of norepinephrine, dopamine, and serotonin (NDSRI) with a potency profile of NET > DAT > SERT, without triggering active neurotransmitter release like traditional stimulants. 1
Mechanism of Action
Centanafadine represents a fundamentally different approach from existing ADHD medications:
Unlike amphetamines (which enter presynaptic neurons and actively trigger monoamine release), centanafadine passively blocks reuptake transporters without inducing neurotransmitter release 1
Unlike methylphenidate (which selectively blocks only dopamine and norepinephrine reuptake), centanafadine inhibits all three monoamine transporters simultaneously 1
The triple mechanism targets norepinephrine most potently, followed by dopamine, then serotonin—a combined catecholaminergic and serotonergic approach designed to manage ADHD symptoms while potentially reducing abuse liability, insomnia, and cardiovascular risks typical of traditional psychostimulants 1
Clinical Efficacy
The medication demonstrates meaningful clinical benefits:
Core ADHD symptoms: Meta-analysis of 5 RCTs (n=1,968) showed significant reduction in ADHD symptom severity versus placebo (Hedges' g = -0.37, p=0.032), with small-to-moderate effect sizes (0.28-0.40) 2, 3
Executive functioning: Clinically significant improvements observed as early as Week 1, with 50% greater chance in children and 88% greater chance in adolescents of experiencing clinically meaningful improvement compared to placebo 4
Learning problems: 79% greater chance in children and 81% in adolescents of experiencing clinically meaningful within-patient change 4
Global severity: CGI-S scores improved significantly (mean difference = -0.26, p=0.0006) across 4 RCTs 2
Safety Profile
Long-term data from 52-week open-label trials in adults (n=653) showed:
Most common adverse events: Insomnia (8.0%), nausea (7.7%), diarrhea and headache (7.0% each)—mostly mild to moderate 5
Discontinuation rate: 12.3% discontinued due to adverse events 5
Serious adverse events: Only 1.8% experienced serious adverse events, none deemed related to centanafadine by investigators 5
Overall tolerability: Meta-analysis showed numerically higher but non-significant risk of adverse events compared to placebo (RR=1.29,95% CI 0.97-1.71) 2
Clinical Context
Centanafadine fills a therapeutic gap as a non-stimulant option with demonstrated efficacy on ADHD core symptoms, executive functioning, and learning problems. While effect sizes are smaller than traditional stimulants, the triple reuptake mechanism offers a novel approach for patients who cannot tolerate or do not respond adequately to first-line stimulants 6, 7. The medication's sustained-release formulation provides once-daily dosing, improving adherence compared to multiple-daily-dose regimens 8.
The evidence base includes replicated efficacy in multiple phase 3 trials across both adult and pediatric populations, with generally acceptable tolerability profiles 3, 2. This positions centanafadine as a viable second-line option when methylphenidate or amphetamines are contraindicated, ineffective, or poorly tolerated.