Carbidopa–levodopa

A dopamine precursor combined with carbidopa, FDA-approved for Parkinson's disease and other parkinsonism; inhaled levodopa (Inbrija) treats "off" episodes.

psilodex.org/m/carbidopa-levodopa · 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: ~1.5 h; Approximate, in adults. Source under Interaction below.

Named in state rules?

Not namedColorado Condition rules (3)

Not namedOregon

PendingNew Mexico

Cite asPsilodex, “Carbidopa–levodopa”, v2026.10.05. psilodex.org/m/carbidopa-levodopa

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

Parkinson's disease
Post-encephalitic parkinsonism
Parkinsonism after carbon monoxide or manganese intoxication

Sources [1]

Other safety

The label contraindicates nonselective MAO inhibitors with it and lists narrow-angle glaucoma as a contraindication.

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

Sources [1]

01 Interaction with psilocybin

Levodopa raises brain dopamine, and its effect on psilocybin is unknown. Separately, its label reports hallucinations with dopamine-boosting medicines.

Detail There are no psilocybin data for levodopa. Levodopa raises brain dopamine, and how this changes psilocybin's effects is unknown. Dopamine-boosting (dopaminergic) drugs may add to perceptual or psychotic-like effects. Separately, the label reports hallucinations and psychotic-like behavior with dopaminergic medicines, sudden sleep onset, and depression with suicidal tendencies. It also reports seizures linked to vitamin B6 deficiency. It reports a neuroleptic malignant syndrome-like reaction (a severe drug reaction) with abrupt dose reduction or withdrawal. The label lists nonselective MAO inhibitors as contraindicated with it. Sources [1]

Human data with psilocybin: No psilocybin data; based on how it works and its label
Half-life: ~1.5 h (levodopa with carbidopa) (FDA label, checked 2026-10-04) Levodopa alone ~50 minutes.

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

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]
Withdrawal or rebound if stopped abruptly: Stopping suddenly can cause withdrawal or a rebound of symptoms. Sources [1]
Psychiatric reactions: The label or source warns of psychiatric effects such as psychosis, mania, hallucinations, suicidal thoughts or severe mood or behavior changes. Psilocybin can also bring up strong emotions, so these warnings are relevant to screening. 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 namedCondition rules (3)

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.

Parkinson's disease (severe chronic illness)
- CO 2.5(A)(2) · Clinical Facilitator licensees
- CO 6.16(F)(2)(a) · Facilitators without a clinical facilitator license
- CO 6.16(F)(1) · All licensees

05 Sources

SINEMET (carbidopa and levodopa) tablets (Organon) · FDA label (DailyMed) — Psychiatric reactions: Precautions, Hallucinations / Psychotic-Like Behavior "Hallucinations and psychotic-like behavior have been reported with dopaminergic medications." | Lowers seizure threshold or carries seizure risk: Warnings, Vitamin B6 Deficiency and Seizures "Seizures associated with vitamin B6 deficiency have been reported in the postmarketing setting in patients taking SINEMET." | Sedating or CNS depressant: Warnings "Patients taking SINEMET alone or with other dopaminergic drugs have reported suddenly falling asleep without prior warning of sleepiness while engaged in activities of daily living (includes operation of motor vehicles)." | Withdrawal or rebound if stopped abruptly: Warnings, Hyperpyrexia and Confusion "Sporadic cases of a symptom complex resembling neuroleptic malignant syndrome (NMS) have been reported in association with dose reductions or withdrawal of certain antiparkinsonian agents" | "When carbidopa and levodopa are administered together, the half-life of levodopa is increased to about 1.5 hours."
RYTARY (carbidopa and levodopa) extended-release capsules (Amneal) · FDA label (DailyMed) — brand listing only; label not read
CREXONT (carbidopa and levodopa) extended-release capsules (Amneal) · FDA label (DailyMed) — brand listing only; label not read
DHIVY (carbidopa levodopa) tablets (Avion) · FDA label (DailyMed) — brand listing only; label not read
INBRIJA (levodopa inhalation powder) (Merz) · FDA label (DailyMed) — brand listing only; label not read

Record history

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

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