Rifampin

A rifamycin antibiotic, FDA-approved for all forms of tuberculosis and for clearing meningococcal bacteria from carriers' noses and throats.

psilodex.org/m/rifampin · 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: ~3.4 h; Approximate, in adults. Source under Interaction below.

Named in state rules?

Not namedColorado

Not namedOregon

PendingNew Mexico

Cite asPsilodex, “Rifampin”, v2026.10.05. psilodex.org/m/rifampin

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

Tuberculosis (all forms, with other drugs)
Meningococcal carriers without symptoms (to eliminate Neisseria meningitidis from the nasopharynx)

Sources [1]

01 Interaction with psilocybin

Not studied with psilocybin; it speeds the enzymes that clear psilocybin, so weaker or shorter effects are possible. Separately, its label warns of liver injury.

Detail Rifampin is a potent inducer (speeder) of drug-metabolizing enzymes, including CYP3A4 and UDP-glucuronosyltransferases (UGT). UGT is the main route the body uses to clear psilocin (psilocybin's active form). So rifampin may lower psilocin levels and shorten or weaken psilocybin's effects; there are no psilocybin data. Separately, its label warns of hepatotoxicity (liver injury). Sources [1][2]

Human data with psilocybin: No psilocybin data; based on how it works and its label
Half-life: ~3.4 h (single dose); 2–3 h with repeated dosing (FDA label, checked 2026-10-04) Mean 3.35 h after a 600 mg oral dose; shortens with repeated administration (enzyme self-induction).

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

2 listed · counted on reports

Speeds up drug metabolism: Increases the liver enzymes that break down many medicines, lowering their levels. When it is stopped, levels of other medicines can rise over the following weeks. Sources [1]
Liver injury: The label or source warns of liver injury, from raised liver enzymes to liver failure. Liver disease also affects how the body clears psilocin. 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 2026-10-04

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

None linked

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

05 Sources

Rifampin capsules (Lupin) · FDA label (DailyMed) — revised 2026-02 | Speeds up drug metabolism: Warnings "Rifampin has enzyme-inducing properties, including induction of delta amino levulinic acid synthetase." | Drug Interactions "Drug metabolizing enzymes and transporters affected by rifampin include cytochromes P450 (CYP) 1A2, 2B6, 2C8, 2C9, 2C19, and 3A4, UDP-glucuronyltransferases (UGT), sulfotransferases, carboxylesterases, and transporters" | Liver injury: Warnings "Hepatotoxicity of hepatocellular, cholestatic, and mixed patterns has been reported in patients treated with rifampin." | Clinical Pharmacology "mean biological half-life of rifampin in serum averages 3.35 ± 0.66 hours after a 600 mg oral dose" "With repeated administration, the half-life decreases and reaches average values of approximately 2 to 3 hours."
Thomann J, Kolaczynska KE, Stoeckmann OV, et al. In vitro and in vivo metabolism of psilocybin’s active metabolite psilocin. Front Pharmacol 2024;15:1391689. — Abstract: "recombinant CYP2D6 and CYP3A4 enzymes metabolized nearly 100% and 40% of psilocin, respectively." "MAO-A transformed psilocin into minimal amounts of 4-HIAA and 4-HTP." "In conclusion, MAO-A, CYP2D6, and CYP3A4 are involved in psilocin's metabolism." Introduction: "Around 33% of a psilocybin dose is renally excreted as 4-HIAA."

Record history

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

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