IDRA-21 is an ampakine drug and a benzothiadiazine derivative. IDRA-21 is a chiral molecule, with (+)-IDRA-21 being the active form.
IDRA-21 shows nootropic effects in animal studies, significantly improving learning and memory. It is around 10-30x more potent than aniracetam in reversing cognitive deficits induced by alpraz or scopolamine, and produces sustained effects lasting for up to three days after a single dose. The mechanism for this action is thought to be through promoting the induction of long-term potentiation between synapses in the brain.
IDRA-21 does not produce neurotoxicity under normal conditions, although it may worsen neuronal damage following global ischemia after stroke or seizures.
In comparison to the benzoylpiperidine derived ampakine drugs, IDRA-21 was more potent than CX-516, but less potent thanCX-546. Newer benzothiadiazide derivatives with greatly increased potency compared to IDRA-21 have been developed, but these have not been researched to the same extent, with the benzoylpiperidine and benzoylpyrrolidine CX- series of drugs being favoured for clinical development, most likely due to more favourable toxicity profiles at high doses.