Cardiac & Physiological Screening

Why cardiac screening is the floor, not paperwork

Every modality this standard covers can move blood pressure or heart rate. Only one of them — ibogaine — can kill a physically healthy patient through a specific, well-characterized cardiac mechanism, at a therapeutic dose, with no warning from a normal history. That is why cardiac and physiological screening sits in the Common Core as a universal requirement, and why ibogaine carries its own annex on top of it. This module uses ibogaine as the worked example because it is the clearest, highest-stakes case for the discipline every modality needs. Established

The mechanism: hERG blockade, QT prolongation, and Torsades de Pointes

Ibogaine and its long-lived active metabolite noribogaine block the cardiac hERG potassium channel — the current that normally repolarizes the heart after each beat. Patch-clamp studies put the blocking potency of both compounds in the low-micromolar range, with noribogaine slightly more potent than the parent drug. Delayed repolarization lengthens the QT interval, and a sufficiently prolonged QT interval creates the electrical substrate for Torsades de Pointes, a polymorphic ventricular tachycardia that can degenerate into ventricular fibrillation and sudden cardiac death. Established

A 2016 systematic literature review documented at least 27 ibogaine-associated fatalities in the published case-report record up to that point — a literature snapshot, not a live registry, so the true cumulative number today is almost certainly higher. Among the case reports with adequate clinical or post-mortem detail, eight occurred in people with no pre-existing cardiovascular disease and no family history of cardiac problems. Cardiac risk with ibogaine is not confined to patients who already carry a cardiac diagnosis — that single fact should change how you screen everyone. Established

Why the risk outlasts the dosing session

Noribogaine has a much longer elimination half-life than ibogaine and remains at clinically relevant concentrations for days after ingestion. In one closely monitored clinical cohort (opioid-dependent adults given a single weight-based oral dose under continuous observation), the average maximum QTc prolongation was about 95 ms, half of the patients reached a QTc over 500 ms at some point, and in six of fourteen patients the QTc stayed above 450 ms for more than 24 hours post-dose. No Torsades de Pointes occurred in that cohort — which is itself the argument for why that level of monitoring is the standard, not an option. Established

Practical implication: cardiac monitoring cannot end when the visible acute session ends. Build a monitoring plan around the window noribogaine is still active, not just the hours immediately after dosing.

Reading the QTc: thresholds that should change your plan

Two thresholds anchor most drug-induced QT risk stratification in the general cardiology and pharmacy literature: an absolute QTc greater than 500 ms, and an increase of 60 ms or more from the patient's own baseline. Either one alone is an established marker of meaningfully elevated Torsades de Pointes risk — a patient does not need to meet both. Risk factors that stack on top of a borderline QTc include hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, older age, female sex, structural heart disease or reduced ejection fraction, diuretic use, and any interacting drug that raises plasma levels of a QT-prolonging agent. Established

None of these thresholds are ibogaine-specific — they are the same criteria pharmacists and cardiologists use to flag any QT-prolonging medication. What is ibogaine-specific is how often patients reach them and how long the elevation persists, per the monitoring data above.

CYP2D6 and medication reconciliation: the same dose is not the same exposure

Ibogaine is converted to noribogaine primarily by the CYP2D6 enzyme. In a controlled human pharmacokinetic study, pretreating healthy volunteers with the CYP2D6 inhibitor paroxetine roughly doubled their total exposure to the combined active moiety (ibogaine plus noribogaine) compared with placebo pretreatment — chemically phenocopying a poor metabolizer. The study authors explicitly recommended genotyping patients before ibogaine treatment and at least halving the dose in confirmed CYP2D6 poor metabolizers. Established

• Screen the full medication and supplement list for CYP2D6 inhibitors — several SSRIs, including paroxetine and fluoxetine, are common ones in a veteran population.
• Screen separately for other QT-prolonging drugs (certain antiarrhythmics, some antipsychotics and antiemetics, some macrolide antibiotics) — these stack with ibogaine's own QT effect regardless of CYP2D6 status.
• Any tapering or discontinuation of a serotonergic or interacting medication is a prescriber decision, never something initiated by an education program or supplement protocol.
• Where genotyping is not available, treat the patient as a possible poor metabolizer and build in dose caution rather than assuming average metabolism.

Electrolytes and magnesium: a precondition, not a proven cardioprotectant

Correcting potassium, magnesium, and calcium before dosing is not a formality. Hypokalemia, hypomagnesemia, and hypocalcemia are independently established risk factors for Torsades de Pointes, and intravenous magnesium sulfate is the standard emergency treatment once Torsades has already occurred. Established

Some ibogaine protocols — including a Stanford open-label study in Special Operations veterans with traumatic brain injury — co-administer magnesium alongside ibogaine as a precaution, and that cohort reported no unexpected serious adverse events. That is a reasonable, mechanistically grounded harm-reduction practice — magnesium's antiarrhythmic role is well established in other clinical settings — but it has not been tested in a controlled trial designed to show it prevents Torsades de Pointes specifically in ibogaine dosing. Treat prophylactic magnesium loading as a plausible adjunct to, never a substitute for, baseline ECG, electrolyte correction, and continuous monitoring. Plausible

Cardiovascular risk is not identical across modalities

The Common Core's cardiovascular baseline applies to every modality, but the signature risk differs, and that should shape what you watch for once ibogaine-specific screening is complete.

• Ibogaine — hERG blockade, QT prolongation, risk of fatal arrhythmia; the acute cardiac outlier in this group.
• MDMA — raises blood pressure and heart rate, and carries a separate, non-channel risk of serotonin syndrome and hyperthermia when combined with serotonergic medications; still warrants cardiovascular assessment and caution in hypertension.
• Ketamine — transient rise in blood pressure and heart rate with acute dosing; the more established long-term risk is dependence and urinary tract toxicity, not arrhythmia.
• Psilocybin and LSD — transient blood pressure and heart rate elevation; medical toxicity is low in controlled settings, with psychiatric contraindications the dominant safety concern.

Even a well-resourced, late-stage drug program is not exempt from this discipline: when the FDA declined to approve an MDMA-assisted therapy application in 2024, insufficient cardiac and QT-prolongation safety data in the submission was one of the cited concerns. Rigorous cardiac screening is not an artifact of underground ibogaine clinics — it is a live regulatory expectation across the whole field.

The cardiac go/no-go gate: contraindications and who decides

The standard flags the domains; your named clinician-of-record sets the exact numeric thresholds and makes the go/no-go call. That decision is never automated by a checklist or delegated to an education module. Domains that should trigger a hold, and typically a cardiology consult before any decision to proceed, include:

• Significant or uncontrolled cardiovascular disease or arrhythmia, or a personal or family history of congenital long QT syndrome or unexplained sudden cardiac death.
• An uncorrected electrolyte abnormality — potassium, magnesium, or calcium out of range at the time screening is reviewed.
• A baseline QTc that is already prolonged, or that would foreseeably cross 500 ms or rise 60 ms or more once ibogaine and noribogaine are on board.
• Significant hepatic or renal impairment that would meaningfully alter clearance and exposure.
• A concurrent medication that is a strong CYP2D6 inhibitor or an independent QT-prolonging agent and cannot be safely paused or substituted by the treating prescriber.

Any one of these is a stop, not "monitor closely and proceed."

The bottom line for the chart

Ibogaine can cause a fatal arrhythmia in a patient with a structurally normal heart, at a therapeutic dose, through a well-understood and reproducible mechanism. That is why cardiac and electrolyte screening is graded Established rather than Plausible in this standard — it is the piece of readiness screening with the least room for judgment calls. Whether broader "terrain optimization" changes psychedelic treatment outcomes remains an open question this standard's registry is built to test. Hypothesis Whether an uncorrected electrolyte or an unscreened CYP2D6 interaction can kill a patient is not a hypothesis at all.