Last reviewed 2026-05-30 · How we verify

Acepromethazine (ACEPROMETAZINE)

Phase 2 active Small molecule ✓ Verified May 2026

Acepromethazine (generic name: ACEPROMETAZINE) is a drug. It is currently in Phase 2 development for Insomnia.

Acepromethazine works by blocking histamine receptors in the brain to promote sleep.

Acepromethazine is a small molecule medication. It is also known by other names, including Aceprometazina, Aceprometazine, and CB 1664.

Likelihood of approval

12.3% vs 15.3% industry baseline

If approved by FDA: likely 2031–2034

Steps remaining: Phase 3 → NDA/BLA submission

Confidence: Medium

Why this estimate

Baseline phase 2 → approval rate +15.3pp
Industry-wide phase 2 drugs reach approval ~15.3% of the time (BIO/Informa 2023 industry benchmark across all therapeutic areas).
CNS / neurology attrition -3.0pp
CNS drugs have historically high Phase 3 failure rates (notably in Alzheimer disease + major depression).

Predicted approval windows by jurisdiction (conditional on FDA approval)

Regulator	Country	Likely year	Lag vs FDA
FDA	US	2031–2034	—
EMA	EU	2032–2035	+0.7 yr
MHRA	GB	2032–2035	+0.7 yr
Health Canada	CA	2032–2036	+0.9 yr
TGA	AU	2032–2036	+1.2 yr
PMDA	JP	2032–2036	+1.5 yr
NMPA	CN	2033–2037	+2.3 yr
MFDS	KR	2032–2036	+1.4 yr
CDSCO	IN	2032–2037	+1.8 yr
ANVISA	BR	2033–2037	+2.3 yr

Hover any row for the lag rationale. Lag estimates are reduced when the drug has FDA Breakthrough or EMA PRIME designation (sponsors file globally in parallel).

Estimate based on the BIO/Informa industry phase transition rates plus per-drug modifiers for therapeutic area, sponsor type, FDA designations, mechanism, and trial design. Per-jurisdiction lags from Tufts CSDD international approval studies. Not investment, clinical or regulatory advice. Methodology: /methodology#likelihood.

At a glance

Generic name	ACEPROMETAZINE
Target	Histamine H1 receptor
Modality	Small molecule
Therapeutic area	Neuroscience
Phase	Phase 2

Mechanism of action

Imagine histamine as a key that unlocks a door in your brain, making you feel awake and alert. Acepromethazine is like a lock that blocks that key, preventing histamine from doing its job and helping you fall asleep. This allows you to get a good night's rest and feel more refreshed in the morning.

Approved indications

Insomnia

Common side effects

No common side effects on file.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

Acepromethazine CI brief — competitive landscape report
Acepromethazine updates RSS · CI watch RSS

Frequently asked questions about Acepromethazine

What is Acepromethazine?

Acepromethazine (ACEPROMETAZINE) is a Small molecule drug, indicated for Insomnia.

How does Acepromethazine work?

Acepromethazine works by blocking histamine receptors in the brain to promote sleep.

What is Acepromethazine used for?

Acepromethazine is indicated for Insomnia.

What is the generic name of Acepromethazine?

ACEPROMETAZINE is the generic (nonproprietary) name of Acepromethazine.

What development phase is Acepromethazine in?

Acepromethazine is in Phase 2.

What does Acepromethazine target?

Acepromethazine targets Histamine H1 receptor.

Target: All drugs targeting Histamine H1 receptor
Therapeutic area: All drugs in Neuroscience
Indication: Drugs for Insomnia

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing