discontinued 2008
none citedspec sheet5 rows
Elzasonan was Pfizer's bet on serotonin autoreceptor blockade as an SSRI booster; rather than being a standalone antidepressant, it was designed as a 5-HT1B/1D receptor antagonist meant to be added on top of sertraline to accelerate or deepen the antidepressant response, the same augmentation logic that pindolol trials had explored years earlier. The combination program moved through clinical testing but was shelved in 2008 with no efficacy data ever published, a quiet ending typical of augmentation strategies that could not clear the bar. Its main legacy is as a pharmacological tool compound used to characterize 5-HT1B/1D receptor pharmacology in the lab, long after the clinical program folded.
- none established; no published human efficacy data exists
- served as a useful research tool for probing 5-HT1B/1D receptor pharmacology
- Elzasonan is still sold today, not as a drug, but as a lab reagent for studying 5-HT1B/1D receptor pharmacology.
Mechanism
Selective at 5-HT1B and 5-HT1D autoreceptors, metabolized via oxidative N-demethylation, N-oxidation, and aryl hydroxylation; blocking these autoreceptors was intended to boost serotonin release when combined with an .
Safetyrisks and cautions, not medical advice
Elzasonan's most concrete safety finding is a laboratory one and it does not read comfortably. Human metabolism work showed it forms a reactive iminium ion that binds covalently to protein in liver microsome incubations, the kind of result that flags a risk of unpredictable liver or immune reactions long before any patient reports one. Its main clearance route is CYP3A4, so drugs that inhibit or induce that enzyme would move exposure around, and its half-life runs about 31 hours. Against that, 262 outpatients took it alongside sertraline in a Phase II trial whose results were never released, so no clinical answer exists.
History
Developed by Pfizer in the early 2000s as an SSRI add-on therapy; tested in combination with sertraline for depression and anxiety, then discontinued in 2008 without published clinical efficacy data.
Subjective profileweighing the evidence above
A shelved augmentation strategy whose real trial results never saw daylight, so judge it as unproven rather than as a clear failure.
Resources
This entry is here for reference.
Reviews
My notesprivate to this device
FAQ
Did elzasonan work as an SSRI booster?
Nobody outside Pfizer really knows; the add-on trial to sertraline was discontinued in 2008 and the clinical results were never published.
What receptor did elzasonan target?
5-HT1B and 5-HT1D autoreceptors, not the 5-HT1A receptor targeted by azapirones like buspirone or gepirone.
Limitations of the evidence
- no published human tolerability data from the sertraline add-on trials