Risperidone

Clinical contraindication: Relative; Substantial clinical concern; the literature treats it as a reason for caution or deferral.
Best available evidence: Controlled trial
Half-life: 3 h; Approximate, in adults. Detail in 01.

Named in state rules?

CONamed

ORNot named

NMPending

Cite asPsilodex: risperidone · v2026.10.02

Clinical data and state rules are separate facts. Both are shown; neither is a decision.

01 Interaction with psilocybin

RCT

Pretreatment attenuated psilocybin effects dose-dependently (0.5 and 1 mg; Vollenweider 1998). Reported to worsen persisting visual disturbance after LSD in three cases (Bazire 2018). LAI persists.

Human data with psilocybin: Human studies with psilocybin
Half-life: 3 h (extensive metabolizers), 20 h (poor) / 9-hydroxyrisperidone 21–30 h; active moiety ~20 h (FDA label, checked 2026-09-30)

Evidence types on this record

RCTControlled trial

02 Pharmacology relevant to psilocybin

1 listed · counted on reports

Blocks 5-HT2A (may blunt effects): Blocks the 5-HT2A receptor, the main receptor psilocybin acts through. Can reduce or block the psilocybin effect. Sources [1]

03 State rules

Official text governs

CO4 CCR 755-1

Named · 2.2(A)(6)–(7) · 2.5(A)(2)

Antipsychotic medications are named in rule, regardless of indication or dose. A Facilitator licensee may not provide services to a participant taking one without a referral for natural medicine services from a licensed provider, medical clearance from their medical or behavioral health provider, or a consultation and risk review with a medical or behavioral health provider. A Clinical Facilitator who does not prescribe antipsychotics within their secondary license needs clearance from, or a consultation and risk review with, such a provider.

Colorado · checked 2026-09-30

OROAR 333-333

Not named

No provision names this medication or its class.

Oregon · checked 2026-09-30

NM7.35.3 NMAC (proposed)

Pending

New Mexico's clinical rules (proposed 7.35.3 NMAC) are not final. No provision naming this medication has been found.

New Mexico · checked 2026-09-30

04 Conditions to ask about

Screening items in state rules

This medication is usually taken for a condition. State rules screen for some conditions directly, so the medication is a prompt to ask about them. Confirm with the participant; never assume a condition from the medication.

Psychotic disorder or bipolar disorder (common indications)CO 2.2(A)(6)–(7) · CO 2.5(A)(2) · OR 333-333-5050(3)(j)

05 Sources

Risperidone — prescribing information · FDA label (DailyMed)
Vollenweider FX, Vollenweider-Scherpenhuyzen MFI, Bäbler A, Vogel H, Hell D. Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 agonist action. NeuroReport 1998;9:3897–3902.
Halman A, Kong G, Sarris J, Perkins D. Drug–drug interactions involving classic psychedelics: a systematic review. J Psychopharmacol 2024;38(1):3–18.
Bazire S. Psychotropic Drug Directory 2018. Lloyd-Reinhold Publications, 2018.

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