RESEARCH MONOGRAPH · KDC-MN-254

Tofisopam

May 9, 2026 Kodiac biolabs Research Revised May 19, 2026 2 min read

Our opinion on this compound

66/100

The Hungarian 2,3-benzodiazepine that doesnt sedate, doesnt addict, and still nobody outside Eastern Europe knows it exists

Honestly, tofisopam is one of the genuinely interesting underrated compounds in the anxiolytic space. The 2,3-benzodiazepine ring isomer (most clinical benzos are 1,4-fused) means it doesnt bind the canonical GABA-A benzodiazepine site, which is why it has none of the sedation, anterograde amnesia, motor impairment, or dependence profile that defines that class. Synthesized at EGYT in Budapest in 1966, marketed as Grandaxin since the 70s in Hungary and a handful of other countries, and basically unknown in the US and most of Western Europe.

The mechanism is partly still a puzzle, which is what makes it scientifically interesting. There's evidence for PDE10A and PDE2 inhibition, modulation of striatal dopamine signaling, possible effects on the adenosine A2A receptor, and indirect actions on the HPA axis. It's not a clean single-target compound, and the trial data (mostly Hungarian, Russian, Czech) shows a profile that looks more like an anti-stress modulator than a classical anxiolytic. Useful for autonomic anxiety symptoms, day-to-day stress reactivity, mild cognitive complaints in older populations.

What we like is exactly this messiness. Tofisopam is a research tool for asking whether you can dissociate the anxiolytic effect of GABA-A modulation from the sedative and dependence-forming effects, and the answer seems to be that you can if you stop binding the alpha1 site at all. It's also a useful comparator for newer ligands trying to do GABA-A subtype-selective work.

The trial base is real but thin by Western standards. Most of it is Eastern European, sample sizes are modest, modern methodology isnt always present. The compound has decades of postmarketing use in Hungary without significant safety signals, which is its own kind of evidence.

Sourcing is the tricky part. Egis Pharmaceuticals is the legitimate source, but research-grade material from third-party suppliers varies. The stereochemistry matters; tofisopam is chiral and the R-(-) enantiomer is the active anxiolytic. Racemic and single-enantiomer batches show up in research catalogs and they're not the same compound for SAR work.

Worth keeping in the rotation for anyone working on next-generation anxiolytics that arent benzodiazepines. yeah, honestly, this one is genuinely slept on.

Evidence: 55
Mechanism: 50
Reliability: 65
Safety: 85
Sourcing: 60
Value: 75
Signal: 72
Staying power: 65

Plain-language summary Intrigue 56 / 100

Tofisopam (Grandaxin) is an unusual benzodiazepine from EGIS in Hungary, registered in the 1960s. The chemistry is technically a benzodiazepine, but the substitution pattern (a 2,3-fused ring rather than the standard 1,4-fused ring of diazepam and lorazepam) means it does not bind the classic GABA-A benzodiazepine site at all. As a result it produces anxiolysis without sedation, muscle relaxation, cognitive impairment, or dependence. The actual mechanism is not fully worked out, with proposals including phosphodiesterase inhibition and dopaminergic modulation. Approved across Europe and parts of Asia for anxiety and autonomic dysfunction; never approved in the US. Genuinely interesting pharmacologically because it shows that the benzodiazepine scaffold can do more than activate GABA-A. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

2,3-benzodiazepine atypical anxiolytic

A 2,3-benzodiazepine without classical GABA-A activity; a non-sedating anxiolytic marketed in Europe.

Abstract

Tofisopam (1-(3,4-dimethoxyphenyl)-5-ethyl-7,8-dimethoxy-4-methyl-5H-2,3-benzodiazepine; CAS 22345-47-7; molecular formula C22H26N2O4; molecular weight 382.46) is a 2,3-benzodiazepine developed at EGIS (Hungary) in the 1960s and approved in Hungary, France, and other European and Asian markets under the trade name Grandaxin. Distinct from the 1,4-benzodiazepine class (diazepam, lorazepam, etc.) by the position of the nitrogens in the diazepine ring: the 2,3 isomer does not bind the classical benzodiazepine site on GABA-A receptors and lacks the GABA-A-mediated sedation, anxiolysis, and dependence of conventional benzodiazepines. The mechanism is incompletely characterized; possibilities include phosphodiesterase IV inhibition and modulation of dopaminergic signaling. Plasma half-life is approximately 6 to 8 hours; metabolism is hepatic. Approved indications in markets where registered include anxiety disorders, autonomic instability, and post-stress recovery; off-label use in fatigue and reactive depression. Not approved in the US. Used as a reference 2,3-benzodiazepine.

Mechanism of action

2,3-benzodiazepine; does not bind the classical GABA-A benzodiazepine site. Mechanism incompletely characterized; possible PDE IV inhibition and dopaminergic modulation.

Reported research dose ranges

Clinical 50 to 300 mg per oral administration daily, in divided doses. Rodent studies 5 to 50 mg/kg/day.

References

Petocz L. The pharmacological profile of tofisopam. Pol J Pharmacol Pharm 1993.
Rundfeldt C, et al. Tofisopam: a non-sedative benzodiazepine. CNS Drug Rev 2005.
Saletu B, et al. EEG mapping in patients with anxiety: tofisopam. Neuropsychobiology 1990.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

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Tofisopam

Abstract

Mechanism of action

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Abstract

Mechanism of action

Reported research dose ranges

References

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