Pirlindole – Kodiac biolabs

Plain-language summaryIntrigue 51 / 100

Pirlindole (Pyrazidol) is the Soviet-era reversible MAO-A inhibitor, developed at the Soviet Academy of Sciences in the 1970s and registered in the USSR in 1975, several years before Roche’s moclobemide reached European markets. Mechanistically it does the same job as moclobemide (reversible MAO-A blockade) but with a chemical scaffold completely unlike its Western counterpart, plus a side-activity blocking 5-HT2 serotonin receptors that may contribute to its mood effects. Russian and Eastern European clinicians have been using it for nearly fifty years for depression. The Western literature on it is thin, partly because it never went through Western regulatory review and partly because most of its trials were published in Russian-language journals. 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 Kodiac editorial, not peer-reviewed.

Our opinion on this compoundEstablished workhorse

25/100

Soviet RIMA with dual mechanism but murky evidence base and minimal Western research utility

Look, pirlindole has a genuine footnote in psychopharmacology history. Developed at the Soviet Academy of Sciences and registered as Pyrazidol in 1975, it predates moclobemide’s Western arrival by over a decade and makes a credible claim to being the first reversible MAO-A inhibitor in actual clinical use. The pyrazinocarbazole scaffold is structurally distinct from the benzamide class moclobemide belongs to, and the secondary 5-HT2 antagonism gives it a combined pharmacological profile that, on paper, looks more interesting than a pure RIMA story. That combination, RIMA plus 5-HT2 blockade, resembles the rough logic of compounds like mirtazapine, which has real antidepressant signal with a different side-effect signature. So the mechanism isnt boring. It’s just not novel in 2026.

The real problem is the evidence base. Pirlindole’s clinical literature is almost entirely Soviet and post-Soviet, which creates a verification problem that’s hard to overstate. The trials exist, the approvals are real, and the compound has been prescribed in Russia for five decades. But the trial methodology, data accessibility, and replication status don’t map cleanly onto what a Western systematic reviewer or meta-analyst would accept. We’re not saying the compound doesnt work. We’re saying that in 2026, a bench scientist building a research program on MAO-A inhibition would default to moclobemide as the reference RIMA because the supporting literature is accessible, replicated, and methodologically characterizable.

What we’d want someone to understand is the sourcing reality. Outside Russia and a handful of former Soviet states, pirlindole is not registered and is genuinely difficult to source at research quality. That practical constraint compounds the evidence problem. If you want to study the RIMA component in isolation, moclobemide. If you want 5-HT2 pharmacology in isolation, ketanserin or pimavanserin. Pirlindole as a combined probe is conceptually interesting but lacks the accessibility and documentation to function well as a tool.

The RIMA class itself is in an awkward spot. Contemporary monoamine pharmacology interest has shifted toward MAO-B inhibition in neurodegeneration, or toward multimodal combinations pairing serotonin transporter work with specific receptor subtype targeting. Pirlindole doesnt slot cleanly into either conversation. For a narrow comparative pharmacology program studying the Soviet drug development tradition or specifically probing the RIMA/5-HT2 combination in animal models where sourcing is feasible, theres a case. Outside that framing, the research opportunity cost is high and the available alternatives are clearly better documented.

Novelty: 18
Mechanism promise: 30
In-category differentiation: 22
Evidence quality: 22
Translational signal: 35
Research bench value: 22

Rationale Pirlindole is a 50-year-old reversible MAO-A inhibitor whose entire clinical history lives in Soviet and post-Soviet literature, making evidence quality epistemically difficult to evaluate by modern standards. The secondary 5-HT2 antagonism is a mildly interesting differentiator but not sufficient to lift a compound that more selective and better-documented tools can surpass on every axis.

Atypical reversible MAO-A inhibitor

A pyrazinocarbazole RIMA developed in the USSR in the 1970s; the historical Soviet RIMA equivalent.

Abstract

Pirlindole (2,3,3a,4,5,6-hexahydro-8-methyl-1H-pyrazino[3,2,1-jk]carbazole; CAS 60762-57-4; molecular formula C15H18N2; molecular weight 226.32) is a pyrazinocarbazole RIMA developed at the Soviet Academy of Sciences in the 1970s and registered in the USSR in 1975 under the trade name Pyrazidol. The compound is a reversible competitive MAO-A inhibitor with secondary 5-HT2 antagonism contributing to its antidepressant profile. Clinical efficacy has been documented in Soviet and post-Soviet trials in major depressive disorder, dysthymia, and reactive depression; head-to-head data versus moclobemide are sparse. Plasma half-life is approximately 2 to 4 hours; metabolism is hepatic. The compound is well tolerated relative to hydrazine MAOIs and does not require tyramine restriction at clinical doses. Approval is restricted to Russia and former Soviet states; not registered in the US, EU, or other Western markets. Used as the historical reference RIMA from the Soviet pharmacological tradition.

Read the full monograph

The full reference document covers compound identification, discovery and developmental history, mechanism of action, pharmacokinetics, sourcing and quality verification, and a curated reference list. Embedded inline below; download for offline reading.

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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.