Syrian rue / harmala / ayahuasca

Clinical contraindication: Absolute; The clinical literature treats the combination as contraindicated.
Best available evidence: Mechanism only
Half-life: Not recorded

Named in state rules?

CONot named

ORNot named

NMPending

Cite asPsilodex: syrian-rue-harmala-ayahuasca · v2026.10.02

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

01 Interaction with psilocybin

Harmala alkaloids are reversible MAO-A inhibitors; may increase psilocin exposure (MAO-A is one clearance route). MAO inhibition can raise blood pressure with psilocybin (see tranylcypromine); serotonin toxicity is theoretical, with no reported human case.

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

Evidence types on this record

ThMechanism only (theoretical)

02 Pharmacology relevant to psilocybin

3 listed · counted on reports

MAO inhibition: Inhibits monoamine oxidase, the enzyme that breaks down serotonin and other monoamines. MAO also helps clear psilocin, so it can change how strong and how long the psilocybin effect is, and it raises serotonin levels. Sources [1]
Raises blood pressure or heart rate: Raises blood pressure or heart rate. Psilocybin raises both for several hours, so the effects can add. Sources [4][5]
Serotonergic: Increases serotonin activity, for example by blocking its reuptake or releasing it. Psilocybin acts on serotonin receptors, so effects can add together. With antidepressant use, the psilocybin response can be weaker. Sources [2]

03 State rules

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 2026-09-30

04 Conditions to ask about

None linked

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

05 Sources

Preston CL (ed). Stockley’s Drug Interactions, 11th ed. Pharmaceutical Press, 2016., p. 1496
Preston CL (ed). Stockley’s Drug Interactions, 11th ed. Pharmaceutical Press, 2016., p. 1496
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.
Vojtěchovský M, Hort V, Šafratová V. Influence of MAO inhibitors on psilocybine induced psychosis. Activitas Nervosa Superior 1968;10(3):278–279 (via Tap 2025). — class: MAO inhibition (tranylcypromine)
Barnett BS, Koons CJ, Van den Eynde V, et al. Hypertensive emergency secondary to combining psilocybin mushrooms, extended release dextroamphetamine-amphetamine, and tranylcypromine. J Psychoactive Drugs 2024;57(3):297–303. — class: MAO inhibition (tranylcypromine)

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