KDC-MN-239 – Kodiac biolabs

Plain-language summaryIntrigue 65 / 100

Risperidone (Risperdal) is the most prescribed atypical antipsychotic in the world. Janssen brought it to market in 1993 as the prototype of the combined dopamine D2 plus serotonin 5-HT2A blocker design that defined second-generation antipsychotics. Approved for schizophrenia, bipolar mania, and irritability in autism, it is also widely used off-label in dementia behavioral disturbance and various pediatric conditions. At low doses (1 to 2 mg) it acts more like a typical atypical; at higher doses (above 6 mg) the 5-HT2A advantage washes out and it produces extrapyramidal symptoms and prolactin elevation comparable to older haloperidol. Its active leftover is itself sold separately as paliperidone (Invega). Available as a long-acting injection (Risperdal Consta) for adherence support. 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 Kodiac editorial, not peer-reviewed.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

47/100

The canonical D2/5-HT2A reference atypical: indispensable as a probe, not interesting as a discovery target

Look, risperidone is one of those compounds where the score almost writes itself. Approved in 1993, the most prescribed atypical antipsychotic on the planet, a metabolite (paliperidone) that got its own branded approval. The D2/5-HT2A dual antagonism profile was genuinely interesting when Janssen published it, but that was over thirty years ago, and the pharmacology has been beaten to death across thousands of studies. There is no open mechanism question here.

The receptor profile is textbook at this point: D2 at roughly 4 nM Ki, 5-HT2A at roughly 0.16 nM, a 25:1 ratio that drives the atypical character at low doses and collapses into something approaching haloperidol above 6 mg. The dose-EPS relationship is cited in every antipsychotic pharmacology lecture. The active metabolite contribution is fully characterized. The long-acting injectable formulations are mature commercial products. We’re not going to learn something new about risperidone by running another preclinical series on it.

Where it does hold up as a library entry is bench utility. If your lab is interrogating dopamine receptor biology, autism rodent models, antipsychotic-induced metabolic side effects, or the 5-HT2A / D2 interaction in prefrontal circuits, risperidone is the reference compound. Its well-characterized receptor kinetics and extensive pharmacokinetic database make it a reliable anchor for comparison studies. That’s not nothing. The bench value here is real, its just the value of a well-understood reference, not the value of a frontier probe.

Whats genuinely low here is novelty and mechanism promise. The combined D2/5-HT2A antagonist class is completely saturated. Aripiprazole took the partial agonist angle. Clozapine remains the efficacy benchmark with its messy multireceptor profile. Brexpiprazole and cariprazine refined the partial agonist story further. Risperidone sits as the prototype definition of the class, which means investigators in the field use it as a comparator, not an object of investigation. If you’re designing an experiment to answer a novel question about psychosis biology, risperidone is your control arm, not your experimental arm.

The evidence quality and translational scores are legitimately high. Three approved indications, multiple phase 3 programs, long-acting formulations with their own trial bases, decades of post-marketing surveillance. We’re not questioning the clinical reality. But the rubric asks whether a bench scientist should find this compound worth primary research time right now, and the honest answer is almost certainly no unless the goal is characterizing something new against a reliable reference. As a discovery target in 2025, risperidone is basically done.

Novelty: 18
Mechanism promise: 28
In-category differentiation: 40
Evidence quality: 82
Translational signal: 75
Research bench value: 65

Rationale Risperidone is a 1993-approved, fully characterized reference compound whose novelty and mechanism scores are floor-bound by three decades of settled pharmacology; evidence and translational scores are ceiling-bound by its FDA approval across three indications, but those high downstream scores can’t rescue the overall because the rubric weights novelty and mechanism heavily. Bench value is real but narrow: it scores meaningfully as a canonical probe for D2/5-HT2A biology, not as a frontier research target.

Atypical antipsychotic

A benzisoxazole atypical antipsychotic; the most prescribed atypical worldwide and the prototype combined D2 / 5-HT2A antagonist.

Abstract

Risperidone (3-{2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)piperidin-1-yl]ethyl}-2-methyl-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-one; CAS 106266-06-2; molecular formula C23H27FN4O2; molecular weight 410.49) is a benzisoxazole atypical antipsychotic developed at Janssen and approved by the FDA in 1993 under the trade name Risperdal. The receptor profile is the prototype combined D2/5-HT2A antagonist: D2 (Ki approximately 4 nM), 5-HT2A (Ki approximately 0.16 nM, ratio approximately 25:1 favoring 5-HT2A), with secondary alpha-1, alpha-2, and H1 antagonism. At doses below 6 mg the 5-HT2A predominates and EPS is minimal; above 6 mg the D2 antagonism produces dose-dependent EPS approaching haloperidol-like profile. The active metabolite 9-hydroxyrisperidone (paliperidone, marketed as Invega) carries similar receptor profile and contributes substantially to steady-state activity. Risperidone is the most prescribed atypical antipsychotic worldwide. Plasma half-life is 3 hours for parent, 24 hours for paliperidone metabolite. Long-acting injectables (Risperdal Consta, Perseris) provide biweekly or monthly administration. Approved for schizophrenia, bipolar mania, autism-associated irritability. Used as the canonical D2/5-HT2A reference atypical.

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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.

Tag: KDC-MN-239

Risperidone

Abstract

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