Banisteriopsis caapi

severe cardiovascular disease, uncontrolled hypertension

Severe cardiovascular disease is a relative contraindication. Controlled studies document a diastolic blood pressure increase of approximately 9 mmHg at higher ayahuasca doses (0.85 mg DMT/kg), along with mild sympathomimetic effects. While these effects are transient and modest in healthy individuals, they may pose elevated risk in patients with severe cardiovascular compromise.

schizophrenia, schizoaffective disorder, psychotic episodes

Personal history of psychotic disorders (schizophrenia, schizoaffective disorder, psychotic episodes) constitutes an absolute contraindication. Ayahuasca's combined serotonergic pharmacology — MAO-A inhibition enabling oral DMT activity plus direct 5-HT2A agonism — creates elevated risk of acute psychotic reactions in vulnerable individuals. Clinical risk assessment literature and traveller adverse-event reviews consistently identify psychotic disorder history as a primary exclusion criterion.

bipolar disorder type I

Personal history of bipolar disorder type I is an absolute contraindication due to elevated risk of acute adverse psychological reactions. The serotonergic pharmacology of ayahuasca — combining MAO-A inhibition with DMT-mediated 5-HT2A agonism — may precipitate manic or mixed episodes in bipolar I individuals. This is consistently listed as an exclusion criterion in clinical ayahuasca research protocols.

family history of schizophrenia, family history of psychotic disorders

Family history of psychotic disorders is a relative contraindication based on clinical risk assessment principles applied to serotonergic psychedelics. While no direct case reports document psychosis precipitation in ayahuasca users with family history alone (without personal history), the elevated genetic risk warrants clinical caution.

hepatic impairment, CYP2D6 poor metabolizer status, CYP3A4 impairment

Hepatic impairment affecting CYP2D6 or CYP3A4 function is a relative contraindication. Harmine undergoes extensive hepatic first-pass metabolism; impaired hepatic function could result in elevated systemic harmine levels, prolonged MAO-A inhibition, and increased risk of serotonergic adverse effects. CYP inhibition data is primarily in vitro; clinical significance has not been established.

pregnancy

Pregnancy is a relative contraindication due to complete absence of reproductive safety data for B. caapi or ayahuasca preparations. MAO-A inhibition and serotonergic modulation present theoretical risks to fetal development, including disruption of serotonin-dependent neurodevelopmental processes. No published animal or human reproductive toxicity studies were identified.

SSRI use, SNRI use, triptan use, tramadol use, dextromethorphan use, meperidine use

Concurrent use of SSRIs, SNRIs, triptans, tramadol, meperidine, or dextromethorphan is an absolute contraindication. B. caapi's harmine and harmaline produce reversible MAO-A inhibition; combining this with drugs that increase synaptic serotonin via reuptake inhibition or direct release creates mechanistic risk for serotonin syndrome — a potentially life-threatening condition characterized by hyperthermia, agitation, clonus, and hyperreflexia. A minimum 2-week washout period from serotonergic medications is recommended before use.

lithium use

Concurrent lithium use is a relative contraindication based on anecdotal reports in the broader psychedelic literature suggesting seizure and cardiac risk with lithium combined with psychedelics. No clinical case report for lithium specifically combined with ayahuasca was retrieved in literature review. The interaction mechanism is not fully characterized but may involve additive serotonergic effects and lowered seizure threshold.

tyramine-rich food consumption during active MAO-A inhibition

Concurrent consumption of tyramine-rich foods (aged cheeses, cured meats, fermented products) during B. caapi's active MAO-A inhibition window is a class-level relative contraindication. B. caapi's harmine produces reversible (not irreversible) MAO-A inhibition with relatively transient effect. In a survey of 614 religious users (Durante et al. 2021), no hypertensive crises were documented. The traditional dietary restrictions (dieta) observed before ayahuasca ceremonies are partly grounded in this interaction mechanism. The magnitude of tyramine interaction specific to reversible MAO-A inhibition from B. caapi versus irreversible pharmaceutical MAOIs remains uncharacterized.