Promethazine-codeine ("lean")

psilodex.org/m/promethazine-codeine · data v2026.10.02

Clinical contraindication: Relative; Substantial clinical concern; the literature treats it as a reason for caution or deferral.
Best available evidence: Standard practice
Half-life: Not recorded

Named in state rules?

CONot named

ORNot named

NMPending

Cite asPsilodex: promethazine-codeine · v2026.10.02

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

01 Interaction with psilocybin

Codeine (an opioid) plus promethazine, a sedating phenothiazine with anticholinergic effects. With other CNS depressants it can cause profound sedation and slowed breathing; the label also notes seizure risk and withdrawal in physically dependent users.

Human data with psilocybin: None known: no published human data with psilocybin

Evidence types on this record

PrStandard practice; no psilocybin-specific data

02 Pharmacology relevant to psilocybin

4 listed · counted on reports

Sedating or CNS depressant: Slows the central nervous system: drowsiness, slower reactions and impaired coordination, and slowed breathing at high doses. Effects add with other sedating substances. Sources [1]
Anticholinergic: Blocks acetylcholine. Can cause a fast heart rate, dry mouth, reduced sweating and heat intolerance, and confusion, more so at high doses or in combination. Sources [1]
Withdrawal or rebound if stopped abruptly: Stopping suddenly can cause withdrawal or a rebound of symptoms. Any change to the dose is the prescriber’s decision. Sources [1]
Lowers seizure threshold or carries seizure risk: Makes a seizure more likely, or has been linked to seizures. Sources [1]

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 2026-09-30

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 2026-10-02

04 Conditions to ask about

None linked

No condition named in state rules is linked to this medication.

05 Sources

PROMETHAZINE HYDROCHLORIDE AND CODEINE PHOSPHATE solution · FDA label (DailyMed) — profound sedation/respiratory depression with CNS depressants; additive cholinergic-blockade effects; taper in dependent patients; may increase seizure frequency

Record history

v2026.10.02First published.
2026-10-02Last reviewed against its sources.

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