PharmaceuticalADHD agentDopamine-norepinephrine reuptake inhibitorProdrug stimulant

Serdexmethylphenidate

Also known as Azstarys (combination) · KP415 · SDX

Written by enwyReviewed 5 Aug 20262 sources0 comments

Serdexmethylphenidate is a prodrug of dexmethylphenidate, co-formulated with immediate-release dexmethylphenidate as Azstarys (approved 2021) for ADHD. The prodrug is cleaved in the gut to release active drug gradually, giving a long, smooth duration with a lower peak and a reduced abuse signal that earned it Schedule III rather than II.

01 Overview

Serdexmethylphenidate covalently links dexmethylphenidate to serine; it is inactive until enzymatically converted, chiefly in the lower GI tract. Azstarys combines 70% serdexmethylphenidate with 30% immediate-release dexmethylphenidate to cover both rapid onset and extended duration.

Human abuse-potential studies supported a Schedule III classification, lower than the Schedule II of parent stimulants, because intranasal and oral abuse liability of the prodrug is attenuated.

02 Mechanism

Inactive serine-conjugated prodrug hydrolysed in the GI tract to dexmethylphenidate, which then blocks dopamine and norepinephrine transporters.

03 Dosing

Tier	Dose	Route	Notes
Starting	39.2 mg/day	Oral	Azstarys 39.2 mg SDX / 7.8 mg d-MPH once daily starting dose.

04 Effects

Effect	Magnitude	Evidence
Sustained attentionImprovement in ADHD symptoms with onset by 30 min and duration up to 13 hours in laboratory-classroom studies.	n/a	Clinical
Smooth pharmacokineticsLower peak-to-trough swing than immediate-release stimulants, reducing peak-related side effects.	n/a	Clinical

05 Side effects

Effect	Severity	Frequency	Evidence
Decreased appetiteReduced appetite and weight loss.	Mild	Common	Clinical
InsomniaTrouble sleeping with the long duration of action.	Mild	Common	Clinical
Cardiovascular stimulationElevated blood pressure and heart rate.	Moderate	Common	Clinical

06 Legal status

United States

Schedule III controlled

FDA-approved as part of Azstarys; SDX itself is Schedule III. · as of Jan 2026

07 References

Efficacy and Safety of SDX/d-MPH (Azstarys) in Children with ADHDJ Clin Psychiatry, 2021

Azstarys FDA prescribing informationUS FDA, 2021

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.