Lecanemab

An anti-amyloid antibody, FDA-approved for Alzheimer's disease in people with mild cognitive impairment or mild dementia.

psilodex.org/m/lecanemab · data v2026.10.05

Clinical contraindication: None listed; No label contraindication covering psilocybin was found. This is not a finding that the combination has been shown to be without risk.
Psilocybin evidence: No psilocybin data
Half-life: 5–7 days; Approximate, in adults. Source under Interaction below.

Named in state rules?

Not namedColorado

Not namedOregon

PendingNew Mexico

Cite asPsilodex, “Lecanemab”, v2026.10.05. psilodex.org/m/lecanemab

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

What it is used for

FDA status

FDA-approved

FDA-approved for

Alzheimer's disease (mild cognitive impairment or mild dementia stage)

Sources [1]

Other safety

Boxed warning: amyloid-related imaging abnormalities (ARIA), more frequent in ApoE ε4 homozygotes; serious intracerebral hemorrhage has occurred, and the label urges caution with antithrombotic or thrombolytic drugs.

About the medication itself, separate from any interaction with psilocybin.

Sources [1]

01 Interaction with psilocybin

No known interaction with psilocybin. Separately, it can cause brain swelling or microbleeds, and its use implies cognitive impairment, which bears on consent.

Detail There are no psilocybin data for lecanemab and no known pharmacologic interaction; it is a monoclonal antibody not processed by liver enzymes. Separately, its boxed warning describes amyloid-related imaging abnormalities (ARIA: brain swelling or microbleeds). These are usually without symptoms but sometimes serious, including focal neurologic deficits. Its indication implies cognitive impairment, which bears on capacity to consent.

Human data with psilocybin: No psilocybin data; based on how it works and its label
Half-life: 5–7 days (FDA label, checked 2026-10-04)

Evidence types on this record

No psilocybin dataNo psilocybin data: no human data with psilocybin or another classic psychedelic; the text draws on the medication's own pharmacology and its label or reference facts

02 Pharmacology relevant to psilocybin

None listed

No pharmacology properties of concern are listed for this record.

03 State rules

Plain-language summary · official text governs

CO4 CCR 755-1

Not named

No provision names this medication or its class.

Colorado · checked 2026-10-04

OROAR 333-333

Not named

No provision names this medication or its class.

Oregon · checked 2026-10-04

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 2026-10-04

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.

Cognitive impairment or dementia (affects capacity to consent)

05 Sources

LEQEMBI (lecanemab-irmb) injection / LEQEMBI IQLIK autoinjector (Eisai) · FDA label (DailyMed) — Boxed Warning "ARIA is usually asymptomatic, although serious and life-threatening events can occur. ARIA can be fatal." | 12.3 "The terminal half-life is 5 to 7 days."

Record history

v2026.10.02First published.
2026-10-04Last reviewed against its sources.

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